MC How-To
Step by step: From general maintenance to complete restorations, we share tips and tricks for working on classic bikes.


1977 Suzuki GS750 Charging System Upgrade

suzuki charging system upgrade

Charging systems improved markedly in the 1970s, both in terms of output and component quality. But age isn't always kind, and 40 years later, many of those systems are experiencing their share of issues. Burnt or corroded contacts in the charging system wiring are something of a silent killer, creating resistance that heats up the wiring, often leading to stator failure.

That was the case with our subject 1977 Suzuki GS750, which was suffering from low voltage output from the stator to the rectifier/regulator. One of the stator's three output lines was badly burnt at its connector. The rectifier and voltage regulator were working properly, but there wasn't enough voltage output to keep the battery properly charged. The problem most likely started with mild corrosion, then as resistance built and the wires heated up the connection started burning, to the point where voltage output from that phase of the stator was blocked, leading to more problems with the stator itself.

suzuki charging system upgrade

At the same time we were looking into the Suzuki's charging problems, we learned that Rick's Motorsport Electrics was introducing a new line of lithium-ion friendly rectifier/regulators to pair with lithium-ion batteries in vintage bikes. Incredibly light and with no corrosive acid — you can mount them upside down if you want — lithium-ion batteries make great sense, but their use in vintage bikes has been somewhat limited due to the high charging voltage output on many older machines.

In a 12-volt application, a typical lead-acid battery works well with charge rates up to around 14.5 volts, but lithium-ion batteries work best with a lower voltage charge and within a narrower range as they don't like large swings in voltage, something lead-acid batteries tolerate well. Working with lithium-ion battery specialists Ballistic Performance Components, Rick's has developed a line of rectifier/regulators specifically tailored to the voltage output required for lithium-ion batteries.

We wanted to try the new regulator/lithium-ion battery setup, but first we sent our stator to Rick's for refurbishment, getting back a freshly rewound stator with new output leads. The stator rebuild for the Suzuki was $175.95 (an off-the-shelf rebuilt stator is $200.95, with a refundable $50 core charge). The upgraded rectifier/ regulator was $129.95, and the Ballistic EVO2 8-cell lithiumion battery $169.95. You'll also need a side cover gasket, which we got from Z1 Enterprises for $4.95. Rick's one-piece rectifier/regulator replaces the stock separate items, and it also takes all three phases of the Suzuki's stator instead of one of them powering the headlight circuit, a common setup back in the day to provide dedicated voltage to the headlight.

This is a straightforward job, easily within the capabilities of the average weekend warrior. No special tools are required, although we highly recommend having the correct JIS "Phillips" screwdriver for removing and installing the side cover. We used a JIS impact driver as the original side cover screws are notoriously stubborn to remove. We still ended up with several damaged screw heads, so we replaced all the sidecover screws with stainless steel Allen-head screws.

We did experience one unexpected issue that had nothing to do with the install: A corrupted memory card resulted in the loss of all of our photos of the disassembly phase. However, owing to this job's relatively simple nature, we're confident that if you read through our assembly, you'll have a clear idea of how it all comes apart. Remember those manuals that always said, "Assembly is the reverse of disassembly"? Well, this time, just turn that phrase around!

With the new system installed our Suzuki started on the button, which it didn't before as the system wasn't supplying enough voltage to maintain the battery. A check with the engine running, with the headlight on, showed a charging output of 12.8 volts at idle, 13 volts at 2,000rpm and 13.5 volts at 4,000rpm, just where it should be. As always, we recommend having a good shop manual on hand for parts identification and proper torque specs.

suzuki charging system upgrade

  1. The original stator from our Suzuki. Note the burned connector on the white/blue output lead, the source of our problems. As always with any electrical work, the first step is to disconnect the battery, and in this case remove it.
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  3. The stator cover removed, revealing the alternator rotor and starter drive. The stator is contained in the cover. During removal, we disconnected the stator leads at the rectifier, then pulled them gently with the stator and cover, not appreciating you should first remove the sprocket cover, as you'll see.
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  5. The stator is held to the cover by three screws. The stator output leads are secured in their routing in the cover by three metal plates. Note the relief in the stator; it must point down for the stator to fit its mount in the stator cover.
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  7. The stator loosely positioned in the stator cover. Note the orientation of the output lead harness, which tucks into a channel cast into the cover. It follows a clear routing path. The molded wiring grommet should be pressed firmly in place in its recess in the cover.
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  9. The stator firmly screwed into place. Note the metal bracket at roughly 12 o'clock securing the stator leads and keeping them clear of the alternator rotor, and the two additional brackets at roughly 2 o'clock and 3 o'clock holding the stator leads in place.
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  11. Next, we installed the new gasket, with just a dab of sealant to hold it in place. We then fished the stator leads through the opening in the rear cover up into the recess for the starter. We had removed the starter cover earlier, but at this stage we still didn't appreciate that we'd have to remove the sprocket cover.
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  13. The stator leads pass from the starter recess along a channel cast into the engine case before exiting on their way to the rectifier. This is why the cover should be removed first, a point we didn't appreciate during teardown.
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  15. With the stator leads properly routed we removed the stock rectifier, which is screwed to the side of the battery case. We had already disconnected its leads: yellow=stator; white/blue=stator; white/red=headlight circuit; red=power.
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  17. The stock rectifier (right) and the new combined rectifier/regulator. The stock setup sent one leg of the stator's output (white/green) directly to the headlight circuit and then to the rectifier (white/red). The new setup directs all three phases of the stator's output directly to the rectifier/regulator. The white/green and white/red in the wiring harness are simply left unused.
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  19. The stock voltage regulator is mounted under the battery box, which must be removed to access the regulator. The yellow lead went to the old regulator and the black ground lead is secured by the front battery box screw.
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  21. To remove the battery box, first unscrew the starter solenoid; the right screw secures the solenoid mounting panel to the battery box. Lift the mounting panel up to release it from the battery box and leave it free.
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  23. Remove the three battery box mounting screws, two at the rear and one at the front. Note the two ground straps secured at the front screw, one of which goes to the regulator. Pull the battery box straight up and out.
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  25. The battery box removed, with the stock regulator clearly visible. Remove the two screws securing the regulator and remove the regulator.
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  27. Using the two Allen-head screws supplied with the new regulator, secure the new regulator in place in the same location as the original, ensuring the leads will exit to the left side once the battery box is installed and with the regulator's green ground wire securely grounded at one of the mounting screws.
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  29. Reinstall the battery box, making sure to secure the ground lead at the front mount. Slip the starter solenoid mounting panel back in place and secure the solenoid and panel to the battery box.
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  31. Connect the three leads from the stator to the three yellow leads to the rectifier/regulator. It doesn't matter which goes where. Connect the red lead from the rectifier/regulator to the red lead from the bike's wiring harness.
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  33. With the new combined rectifier/ regulator installed the white/blue and white/red leads for the lighting circuit are no longer used. We put heatshrink tubing on the exposed bullet connector of the white/blue wire to make sure it was isolated.
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  35. Install the Ballistic lithium-ion battery. It's much smaller and lighter than the original. We used foam blocks to take up space and keep the battery secure. A plastic tool tray sits over the battery, so there's little risk of it moving vertically. Reconnect the battery.

Installing an Alton Norton Commando Electric Starter

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The Norton Commando is one of the most popular classic motorcycles ever made — and they made lots of them, an estimated 60,000 over an almost 10-year life span. Endowed with excellent handling and a torquey, train-pulling twin, they were the Superbike of their day.

Although electric starting was planned at least by 1970, the first electric-start Commando didn't appear until 1975, the last year of full production. That means that most Commandos, whether 750 or 850, were kickstart only. The Norton lump can be a challenge to kick over, and as the Norton faithful aged, the market for an electric-start conversion grew. There are now several available, including the one from Alton in France that we installed in our subject 1974 Norton Commando 850 MkII.

Applicable to pre-1975 750 and 850 Commandos (except early Fastbacks with the ignition at the rear of the timing cover), the Alton kit uses the stock chain-driven primary and can be used with many belt-drive conversions.

This is a comprehensive and extremely well-designed conversion. The replacement inner primary cover carrying the small but powerful electric starter is beautifully cast and nicely machined. The starter sprag clutch and drive setup seems very robust, and the Alton alternator, rated at a maximum output of 150 watts and 90-95 watts at cruising speed, should provide ample charging. The kit is available for either positive or negative ground systems.

You'll need a higher output battery. U.S. distributor The Classic Bike Experience in Essex, Vermont, where we sourced our Alton starter, suggests an Interstate FAYTX20HL sealed lead-acid battery (pre-1971 bikes require a smaller battery; call CBE for options). We found one locally for $85. CBE also suggests replacing the crankshaft seal. It's cheap (typically only $2 or $3) and easy to replace while the primary cover is off. You'll note that we did not, however, as the seal had been replaced just a few months earlier during a clutch overhaul.

The kit does not include an outer primary case locating dowel. We had to heat the stock case quite hot to break one of the dowels free, and it was a slightly loose fit in the Alton cover, requiring a dab of RTV sealant to hold it in place. New ones are cheap (about $2.50), but this is one item we think should be included with the kit. We'd also suggest having new woodruff keys ($7 to $10) and a new clutch hub locking tab (about $1) on hand. You'll need a puller for the crankshaft sprocket, a clutch hub locking tool, a clutch spring compressor, and a torque wrench.

On post-1971 Commandos the stock switchgear has an unused button, usually the upper right side. Legend says this was included for a proposed starter. You'll have to remove the gas tank, then locate the white/red wire coming out of the switchgear, which terminates in one of the connecting blocks on the frame. It's basically plug and play, but it's a good idea to clean the switch first. Pre- '71 bikes require a separate switch.

This is a detailed job. Give yourself a full weekend and have a Norton service manual on hand; it will help immensely during disassembly. The Alton kit comes with a comprehensive installation guide, with photos to aid installation, and it stresses important points like properly setting the alternator stator air gap and making sure everything is absolutely correct before you attempt to start the engine the first time.

And when you do, you'll probably be as thrilled as we were. The Alton starter spins the Norton engine over easily, providing effortless, reliable starting — without kicking. As a further bonus, when you order your kit from CBE it includes a nice CBE pint glass (gotta have a beer to celebrate when you're done!) and a two-year membership to the International Norton Owners Association.

The kit retails for $2,450. That's hardly an inconsequential sum, but if you want your Norton to start at the touch of a button, we think the Alton kit's quality design and straightforward installation with no permanent alterations make it a good value.

how to

1. Disconnect and remove the battery. Remove the left footpeg and brake pedal assembly. Place a drain pan under the primary cover. Remove the center holding bolt, then the primary cover. Use a rubber mallet to shock the cover free.

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2. Remove the three nuts securing the alternator stator. Remove the stator. Wedge the plastic block supplied in the kit between the primary chain and the crankshaft sprocket to lock the crankshaft, then remove the rotor nut. Using flat tire irons pressed against the back side, leverage the rotor free. Remove the rotor, the woodruff key and any shims.

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3. Remove the clutch adjusting screw, then the clutch diaphragm and clutch plates. Fold back the clutch hub nut washer tab. Lock the clutch hub and remove the clutch hub nut. An air impact wrench will remove the nut without having to lock the clutch hub.

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4. Using a puller, break the crankshaft sprocket from its taper. Protect the crankshaft threads by placing a washer between the puller and the crankshaft stub. The sprocket can be stubborn to remove. Lightly shock the puller bolt with an air impact wrench or rap it lightly with a hammer to break it free.

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5. Once the sprocket is released from its taper, remove the sprocket, clutch drum and chain as a set. Remove the crankshaft woodruff key. Remove the shims and the clutch locating collar on the transmission mainshaft.

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how to

6. Trace and disconnect alternator wires at the main harness. Pry back the tab washers on the three bolts securing the primary cover to the engine. Remove the bolts, washers and the cover. Clean the engine case. Remove the primary cover central locating stud and fit the new Alton stud finger tight.

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7. Clean the engine case. Remove the primary cover central locating stud and fit the new Alton stud finger tight. With a straight edge against the engine case, check the distance between the straight edge and the stud's locating flat. It must be 22mm. Shim if necessary.

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8. Install the Alton inner primary cover and lightly tighten the securing bolts with washers. There's a slim chance the new bolts could contact the crankshaft counterweight. We positioned the crankshaft and measured the distance to possible interference against the length of the bolts and found ample clearance.

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9. Even so, with the Alton primary case in position we slowly turned the engine over to ensure the crankshaft counterweight did not contact the securing bolts. If it does, you have to shorten the securing bolts.

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10. Remove the primary case. Apply blue Loctite to the new central primary case stud threads and tighten it fully with the new coupling nut. Make sure the crankcase mating surface is clean and apply a film of gasket sealant. We used ThreeBond Gray.

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11. Reinstall the Alton primary assembly. Alton suggests using Loctite on the securing bolts. We opted for Permatex Copper RTV sealant to ensure no oil migration through the threads, a somewhat common problem on Commando engines.

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12. Install the clutch locating collar on the transmission mainshaft with the cupped side facing the transmission, followed by the shims. Turn the engine so the crankshaft sprocket keyway is at 12 o'clock and install the woodruff key.

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13. Install the clutch drum, crankshaft sprocket and primary chain as a set. Install the clutch hub tab washer. Apply blue Loctite to the mainshaft threads, then the clutch securing nut. Lock the clutch drum and torque the nut to 40ft/lb. Fold two of the tab washer flats to lock the nut.

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14. Install the clutch plates, clutch diaphragm and circlip. Loosely install the clutch adjusting screw and nut. Turn the engine over to bring the alternator rotor keyway slot to 12 o'clock.

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15. Install the woodruff key and check the fit of the Alton sprag clutch assembly on the crankshaft. It should be a sliding fit. If not, polish the crankshaft with fine emory cloth. If it catches on the woodruff key, carefully file the key as necessary to achieve a smooth sliding fit.

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16. Remove the sprag clutch. Remove the sprag clutch drive gear from the primary cover. Pull it straight out, then up to clear the primary chain. Remove the woodruff key, install the sprag clutch spacer stepped end out, then reinstall the woodruff key.

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17. Install the sprag clutch, the sprag clutch drive gear and chain as a set. An extra set of hands helps to ensure the woodruff key stays in place while positioning the drive gear and pushing the sprag clutch onto the crankshaft and the drive gear into the primary case.

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18. Put the rotor nut on hand tight. Position the drive gear steady plate, passing the bushed end over the end of the sprag clutch drive gear.

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how to

19. Apply blue Loctite to the central shouldered bolt and tighten lightly. Apply blue Loctite to the three steady plate screws and tighten. Tighten the shouldered bolt.

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20. Remove the rotor nut and apply blue Loctite to the crankshaft threads. Lock the crankshaft using the supplied plastic block and tighten the rotor nut to 60ft/lb.

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21. Install the alternator stator. Fit two of the three screws loosely. Insert the supplied plastic shims between the windings and the rotor to set the air gap. If necessary, adjust the air gap by moving the stator sideways. Once set, tighten the two screws, then install and tighten the third screw.

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22. Ensure the air gap clearance is consistent. We marked the rotor face with a black felt pen and checked the air gap every 120 degrees of engine rotation. Connect the stator wires to the two wires in the primary case. It doesn't matter which goes where.

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how to

23. Connect the alternator wires to the factory harness. It doesn't matter which goes where. Locate the factory white/red starter switch wire and connect it to the supplied jumper wire.

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24. Install the battery and the starter relay. Connect the starter switch jumper wire to the spade connector off the relay. Bolt the relay ground wire to the frame. Connect the starter motor cable and the relay to the battery cable. Connect the negative and positive battery cables.

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25. Install the new primary case rubber seal (trim as needed) with the joint at the top. Remove a locating dowel from the original primary case and install it in the Alton. Ours was a loose fit. We secured it with RTV sealant.

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26. Adjust the free play in the clutch and lock the adjusting screw nut. If it won't adjust properly, remove the inspection cover above the kickstarter for the clutch operating lever and confirm the lever is in place. If it has slipped out of place, loosen the clutch adjusting screw, put the lever in place and readjust the clutch free play.

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27. Install the outer cover and add 200cc of 20w/50 motorcycle oil or ATF. Avoid most automotive oils as they are loaded with friction modifiers. Test the starter with plugs out. Install the plugs, test again, then start up and enjoy!

1968 Triumph Bonneville Voltage Regulator Upgrade

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Making sure your charging system is working to full capacity is important on a number of fronts. To begin with, there's the simple issue of generating enough voltage to keep your lights bright. This is particularly important on vintage bikes, which generally have low-capacity charging systems and run low-output headlights, which tend to be dim even with full voltage. And even if your lights are off, there's the issue of generating enough voltage for proper ignition. If you own a decades-old British twin, chances are good you've already ditched the stock ignition points for electronic ignition, a highly recommended upgrade to ensure steady, reliable firing of the spark plugs. However, some electronic ignitions are very sensitive to voltage supply, dropping completely out of circuit if the voltage drops below a certain range. Boyer electronic ignitions, for example, will drop out below 10 volts.

On Sixties and Seventies British bikes, the original Lucas charging system can be prone to failure. By the mid-Sixties, most British motorcycles were using Lucas charging systems with Lucas' silicone diode rectifier for AC to DC voltage conversion and a Lucas zener diode for voltage regulation. Although relatively simple components, after 40-50 years of vibration and exposure, the voltage regulator and rectifier are ripe for replacement. The original-style components are still readily available, but there are better products on the market that deliver superior performance and reliability, like the Podtronics voltage regulator/rectifier we recently installed on Tech Q&A man Keith Fellenstein's 1968 Triumph T120R Bonneville.

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Keith's Bonneville didn't have any particular charging issues, but with a fresh Pazon electronic ignition upgrade, and wanting also to convert to 12-volt negative ground from positive ground, Keith considered it a good move. Adding to the appeal, it's also a relatively cheap and easy conversion. The Podtronics unit was $57 (before shipping), and while we did opt to clip off what became redundant ground lines from the old rectifier to the battery and frame, had we wanted to, we didn't have to make any permanent changes to the original wiring. Keith's bike already had a replacement wiring harness, so we didn't feel bad about altering it in any way as it's not original.

We also like this upgrade because A) it delivers superior performance over stock and B) the only way anyone will know the charging system has been changed is if they lift the seat and see the new Podtronics unit in place of the original Lucas silicone rectifier. On 1968 and up through the mid-Seventies Triumphs the Lucas regulator (the zener diode) is housed in a large, finned aluminum heat sink attached to the bottom of the lower fork yoke. You can leave it in place to preserve your bike's original looks, as we did, or remove it. For the conversion, we isolated the wiring to the zener diode and then tucked it into the headlamp shell.

We also switched the Bonneville's electrical system from 12-volt positive to 12-volt negative ground. The Podtronics will work either way, as will the Pazon electronic ignition. Switching from positive to negative ground is easy, requiring no permanent changes. Finally, we upgraded to an LED headlamp and taillight. The taillight was a Sylvania Zevo 2357R red LED ($24.95 at O'Reilly Auto Parts). We got our H4-style headlight shell ($44.95) and 80-watt LED bulb ($59.95) from Donelson Cycle. You'll also need an H4 headlamp socket and pigtail ($3-$5 at O'Reilly). The lights are much brighter and with a significantly reduced amperage draw, and they'll basically last forever.

As ever, we recommend having a good shop manual on hand for parts identification and proper torque specs.

how to

1) Disconnect the positive lead to the battery, followed by the negative lead. The stock silicone diode rectifier is located behind the battery box. Remove the nut securing the rectifier. Remove the rectifier and disconnect the electrical leads.

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2) The zener diode, which regulates charging voltage, is housed in a large heat sink located on the lower fork yoke. We left it in place to preserve our bike's original look, but it must be taken out of circuit. Remove the ground strap from the bottom of the heat sink, then resecure the heat sink to its mount.

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3) Next, reach behind the heat sink and unplug the brown/white lead running to the zener diode.

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4) We left the wiring to the zener diode in place, isolating it from the system by sealing it in heat-shrink tubing.

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5) Next, we routed the now isolated wires into the headlamp bucket to keep them out of the way.

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6) We also converted our Triumph from positive ground to negative ground, which required swapping the blue/brown and brown/white leads to the ammeter in the headlamp housing, shown here as they were positioned originally, with the brown/white lead already disconnected.

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7) Next, we mounted the new Podtronics regulator/rectifier, securing it with a single bolt to the same locating point as the original rectifier.

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8) We then connected the black lead from the Podtronics to the red ground lead from the wiring loom that previously ran to the ground post on the stock rectifier, wrapping the red lead with black heat shrink tubing to color code it as negative ground after first removing the now unneeded extra red leads that ran from the rectifier to the frame and battery.

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9) Next, we connected the brown/white lead (which we marked with a "+" for positive) previously disconnected from the stock rectifier to the red lead to the Podtronics unit.

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10) Connect the green/white and green/yellow alternator leads that ran to the Lucas rectifier to the yellow leads to the Podtronics unit. The alternator output is AC so it doesn't matter which alternator lead goes to which yellow lead to the Podtronics.

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11) We installed a 15-amp blade-type fuse to the blue/brown power lead from the wiring loom after covering the blue/brown lead with red heat shrink tubing. The eyelet will run to the positive side of the battery.

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12) Here's the battery back in place, with the now red fused power lead running to the positive side of the battery and the formerly red but now black-sheathed ground leads running to the negative side of the battery.

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13) Our Triumph was already running a Pazon electronic ignition. The Pazon will work with either negative or positive ground. With the conversion, the red and white leads had to be swapped.

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14) As wired for positive ground, the red lead from the Pazon ran to the "+" side of the left ignition coil and the white lead ran to switched power. The red lead running rearward from the coil goes to ground.

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15) With the conversion to negative ground, switched power connects to the "+" side of the left coil. The red lead running to ground connects to the white lead to the Pazon.

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16) We replaced the stock headlamp and taillight with LED bulbs. For the headlamp, that meant getting a complete shell compatible with H4-type halogen bulbs, but fitting it with an LED bulb. The replacement headlamp is on the left, the stock to the right.

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17) For the taillight we used a Sylvania Zevo 2357R red LED bulb, which directs the light to the reflector. Like the LED headlamp, it's brighter and uses less power than the standard incandescent bulb, and should last basically forever.

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how to

18) The ammeter gauge tells the tale, the current draw with lights on dropping from 4 amps-plus (top) to less than 2 amps (above).

Having a Blast Using our TP Tools Skat Cat 40 Blast Cabinet

Before and after: The Laverda SF2 fork yokes were pretty rough, but after media blasting they’re ready for fresh paint. Photos by Richard Backus.

We’ve wanted a good media blast cabinet for, oh, like forever, so actually having one makes us almost giggle every time we find an excuse to put it to work. We picked up our TP Tools Skat Cat 40 blast cabinet about a year ago, and since then it’s become a central piece of equipment in the Motorcycle Classics garage, an alchemist's dream that lets you magically turn lead into gold by transforming time-worn parts into like new forms, ready for refinishing. Just recently, we blasted our way through a trio of steering bits; two motorcycle related and one bicycle.

First up was the upper fork yoke on my daughter’s 1980 Moto Guzzi V50. The original plan was to replace the Guzzi’s pitted fork tubes and leaking fork seals. The upper yoke had to come off to pull the tubes, and it seemed pointless to put it back on with its scruffy and worn black paint. Guzzi seems to have gone back and forth on yoke finish at the time, sometimes painting them black and others leaving them in a natural aluminum finish. On the V50, the bottom yoke was a natural aluminum finish and the top was black, so I opted to take the top yoke back to a natural finish.

Previously, I would have used a chemical stripper to remove the original paint. That works OK, but it’s slow and tedious compared to having a blast cabinet, and there’s a fair bit of clean up and final prep to get to a finished result. Using the TP Tools blast cabinet, it took maybe five minutes tops to completely strip the yoke. Once stripped, I worked it over with a buffing wheel, starting with Brown Tripoli compound before moving to White Rouge. That took longer than stripping the yoke, and maybe even a little longer than had I opted to repaint it, but the result is a clean, natural aluminum finish, and it looks excellent back on the bike.

The Moto Guzzi V50 fork yoke before blasting.

The Moto Guzzi V50 fork yoke midway through blasting.

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The Moto Guzzi V50 fork yoke blasted and polished.

Next up was refinishing the ugly off-white handlebar stem on my road bike. The stem was a freebie from a friend, but I wanted a natural finish and was actually on the cusp of getting a new one when I did the Guzzi. I went through the same process as with the Guzzi’s steering yoke, and like the Guzzi, it only took a few minutes to strip. And being a smaller piece, it was a pretty quick job to polish it up. I didn’t go for a mirror finish, but could have if I’d wanted to put in a little more effort.

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The painted bicycle stem.

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The bicycle stem after blasting.

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The bicycle stem after polishing.

That was hardly done when I turned my attention to replacing the steering head bearings on a 1974 Laverda SF2 750. Pulling the yokes off, the paint on the upper yoke was much worse than on the Guzzi, and the lower was no better. Unlike Moto Guzzi, Laverda was consistent with the final finish on the yokes, painting all of them something between a flat to satin black. The paint on the Laverda yokes was thicker than on the Guzzi, so it took a little longer to strip them, taking maybe 10 minutes each to get them how I wanted them. I took both pieces to get powder coated, but haven’t collected them yet. I’ll post picks of the finished yokes shortly.

A quick note on blast media:
We started with TP Tools’ suggested blast media, Skat Magic Abrasive crushed glass. That gave excellent results on aluminum, which is what we’re mostly working with, leaving a perfect base finish ready for primer and paint. When it was time to restock media, we turned to our local Tractor Supply Co. store, where we picked up a 50-pound plastic drum of their house brand U.S. Minerals crushed glass media. Both are rated as medium grit, and both work well, although we think the TP product performs better and lasts longer, and with less dust, which is a downside to crushed glass versus glass beads. The upside? Crushed glass cuts faster. The price was nominally the same, the Skat Magic priced at $31/50 pounds and the TSC glass media priced at $33.99/50 pounds. We’d go back to the Skat Magic if we could, but shipping costs pretty much kill that option for us. Next time around, we’ll stock up with glass beads to see how that media performs relative to the crushed glass. And finally, we’ll also order another air filter for our Skat Blast HEPA Vacuum ($27.95 for a standard filter, $42.95 for HEPA). We’re on our second so far, and we’ll be curious to see if we get longer filter life with glass beads, as the filter seems to load up quicker than we’d expect given our blast cabinet’s relatively light work load. — Richard Backus

Honda CB450 Starter Overhaul

How To

As reliable as vintage Japanese electrical hardware may be, everything has a service life, and that includes the starter motor on our subject 1970 Honda CB450K4, which had been displaying a tendency to drag and otherwise turn slowly making the CB450 somewhat hard to start.

BikeMasterNew starters for the CB450 haven’t been available for some time, and while used starters are — typically for around $50- $90 — it’s possible you’ll end up buying the same problems you already own. That makes rebuilding your starter a good option, and fortunately, kits like the one we got from Honda specialists Common Motor Collective are readily available. The $65 kit we purchased is very comprehensive, with all new wear and service parts including a new drive-end bearing and seal, a new brush plate assembly with brushes, starter housing O-rings and gaskets, planetary gear bushings, the armature support plate bushing, the rear cover bushing, and new fiber gaskets and replacement nuts for the starter battery cable post.

Save for the hassle of having to remove the left side cover, which also houses the alternator, removing the starter on the CB450 is relatively easy. The side cover must be removed, as it’s otherwise not possible to re-engage the starter drive chain once the starter has been removed, as the photos will make clear. First, however, you have to remove the shift lever, followed by the drive chain sprocket cover. Make sure to have a new side cover gasket on hand, typically around $12-$15. Once the starter has been removed, make sure the armature and field coils are good before going any further. You can research how to confirm all of this for yourself using a simple multimeter, but we took both pieces to our local automotive electrical shop, where a quick test confirmed that 1) the armature was running true and the windings weren’t broken or damaged; 2) the commutator end was in good condition with even resistance, needing only a light sanding to clean up the contact face; and 3) the starter field coils were good. If it hadn’t passed these tests, we would have had to look for a used starter and start over.

How To

Getting all parts clean before reassembly is paramount. Brake and electric parts cleaner works best here; just remember it’s nasty stuff, so wear gloves and work in a well-ventilated area. Although not technically complicated, this can be a challenging project as it involves a fair amount of detail. Although the photos don’t show it very well, note that the brush plate keys to the starter body for proper alignment.

We suggest giving yourself a full morning or afternoon so you don’t rush the job; give yourself time to work slowly and carefully. If you can do that, you shouldn’t have any problems, and you might even find it a fun challenge. This project doesn’t require any special tools, although we strongly suggest having the proper JIS “Phillips” drivers and an impact driver for removing the necessary fasteners, especially the neutral switch, which also secures the alternator wiring. A small bench-top tool press comes in very handy, but you can get away without it; you just won’t have as much control when it comes time to press in new bushings and such.

As ever, we recommend having a good shop manual on hand for parts identification and proper torque specs.

How To

1. Disconnect the negative lead to the battery. Disconnect the positive battery lead at the starter (the post is just visible on the end of the starter, under the left exhaust header). Remove the two bolts securing the starter. Remove the starter.

How To

2. Remove the gear shift lever, then the final drive cover. Remove the two screws securing the neutral switch above the sprocket, which secures the alternator wiring. An impact-type driver is recommended as the JIS “Phillips” screws can be tight. The neutral switch is keyed. Note its orientation for reinstallment.

How To

How To

4. With the starter on the workbench, remove the two long bolts holding it together. If the bolts are tight, use penetrant and an impact driver. Remove the bolts, then the rear cover.

How To

5. Place the starter upright on the drive end. Remove the screw securing the lead from the starter motor field coils to the brush assembly.

How To

How To

6. With the brushes still in place, lift the brush assembly and plate straight up and remove it from the starter. Remove the thrust washers from the end of the commutator. Clean and set them aside for reassembly.

How To

7. Remove the drive end of the starter. The drive end is a planetary gear set for starter drive reduction. The starter motor spins the two smaller gears, which spin the starter output shaft. Remove the two small gears and set aside.

How To

How To

8. Remove the armature support plate and any thrust washers under it. Remove the armature and clean it using electric parts cleaner.

How To

How To

9. Flip the drive end over. Remove the keeper ring for the end bearing, then the snap ring on the output shaft. Push the output shaft free of the drive end housing. Remove the thrust washer from the shaft. Clean it and the shaft and set aside for later reassembly.

How To

10. Place the housing on wooden blocks or a vise (as shown) and drive out the end bearing using a flat punch. It should come out fairly easily.

How To

11. With the bearing removed, use a seal extractor or suitable tool to remove the drive housing seal. Thoroughly clean the housing.

How To

12. The original bearing features a metal shield on the engine side, while the replacement bearing has rubber shields on both sides. It could be argued that change makes the starter seal unnecessary. Regardless, we did install the new seal, which should be pushed into place with the open side up.

How To

13. With the seal seated in the housing, install the bearing using a bearing driver, making sure it’s inserted deep enough for the securing clip to be installed. Install the clip. Push the output shaft with thrust washer installed back into place and reinstall the snap ring.

How To

14. To remove the bushings in the planetary gears, we supported the gears on a suitably sized socket (open end up), then used a small press and a 1/4-inch drive, 5/16-inch deep-well socket to push the old bushings out.

How To

15. The new bushings are chamfered at one end to ease installation. Start the bushing by hand making sure that it’s square with the gear, then press it fully home using the press.

How To

16. Install the rebushed gears onto the output shaft, making sure they turn freely on their posts and that the entire gear assembly turns freely. Lubricate the gear teeth with grease.

How To

17. Clean the armature support plate, removing any old gasket material. Press out the shouldered bushing in the plate, then press the new bushing in with the shoulder in the same orientation. Install the new support plate gaskets with the narrow gasket facing out and the wide gasket to the inside of the starter.

How To

How To

18. Slip the cleaned armature back into the starter body. Install any thrust washers removed earlier, followed by the armature support plate. Loosely install the drive end housing.

How To

19. To remove the rear bushing, we first tapped 8mm threads into the bushing. We then threaded a bolt into the bushing, through a flat plate placed over the cover opening. Tightening the bolt pulled the bushing out easily.

How To

How To

20. With the bushing out, remove and save the felt oil wick as the kit does not include one. Clean the cover. Reinstall the wick and press the new bushing in flush. Oil the bushing.

How To

21. Stand the starter on the drive end. Install the new O-ring seal on the starter body. Pull the brush springs back and slip the brush plate over the commutator. Ensure the coil wire aligns with the insulated brush set and the tang in the plate aligns with the notch in the starter body. Attach the field coil wire.

How To

22. Replace the thrust washers removed earlier. Smear a thin film of oil on the end of the armature shaft. Install the rear cover, making sure the brush plate is properly aligned.

How To

23. With the rear cover in place, install the two long Phillips bolts through to the front housing and screw them home tight. Turn the starter by hand to ensure it does not bind.

How To

24. Install the new O-ring on the drive end housing and grease lightly. Remove the old starter cable nuts and insulators and replace them with the new ones in the overhaul kit.

How To

25. Hold the starter drive chain and sprocket in position and install the starter, making sure the sprocket and starter drive ends spline together.

How To

26. Secure the starter with the two bolts. Ensure the sealing surfaces for the engine and side cover are clean. Install a new gasket. The dowels will hold it in place. We did not use any sealant.

How To

27. Finally, reinstall the side cover with the alternator, the alternator wiring securing plate, the final drive cover and the shift lever. Secure the positive battery lead to the starter. Connect the negative lead to the battery. If everything went right, your starter should spin right over.

Installing an Electronic Ignition on a 1973 BMW R75/5

We appreciate that many BMW owners are perfectly satisfied with their stock breaker points ignition system, but we also think that upgrading to electronic ignition is desirable if you ride your old airhead regularly. For one, the stock points on the /5 are hard to adjust. Camshaft actuated, they’re obscured by the mechanical advance unit, making confirmation of proper gap difficult. Further, showing almost 80,000 miles, our subject 1973 R75/5 was developing an odd propensity for points slip, likely from the points lift block wearing. The points were new BMW replacements, but were requiring regular adjustment. And while the mechanical advance unit looked to be OK, with good springs and no indication of undue wear, it appeared to be hanging up, sometimes sticking at full advance.

BikeMasterFollowing our excellent experience with Euro MotoElectricscharging system upgrade for the BMW /5, we decided to check out their EnDuraLast Electronic Ignition upgrade for the /5 and later airhead boxer twins.

This isn’t a difficult project, but it does require patience. The trigger and sensor are easy to install and the sensor wires route out the top of the front cover. To aid routing, we cut a relief in the grommet for the charging wires and ran the sensor wires alongside them, making sure they wouldn’t be pinched when the front cover was installed. A dab of silicone seals it up. 

The control module has three curves. Curve 1 is the default and provides 34 degrees of advance. Curve 2 is for dual-plug heads and provides 28 degrees advance and Curve 3 (which is what we used) is in the middle, providing 32 degrees advance and a slower advance rate than Curve 1. An optional 9-curve module is also available. Installing the module was straightforward and ignition timing was a cinch: With the engine on top dead center, slowly rotate the trigger wheel clockwise until the gap in the wheel passes the sensor and the red light on the sensor board illuminates. Continue to rotate until the light just goes out. After locking the trigger wheel in place, a check with a timing light showed we were absolutely spot on. 

One important note: The otherwise excellent and detailed installation manual says to remove the spark plug caps before adjusting the trigger wheel. This is incorrect, a point verified in a phone call to Euro MotoElectrics. The spark plugs must be connected and grounded, otherwise the module could be damaged when it fires. Never remove a plug lead from a running engine with this system. Also, as the optical sensor is light sensitive the ignition system will likely drop out if the sensor is exposed to direct sun during tuning or, say, a test ride, with the front cover off.

A side benefit of the system is the fact that you can leave the stock points and wiring in place as a backup in the unlikely event of module or sensor failure. If that happens, simply disconnect the module from the circuit, reconnect the points lead at the coil and reinstall the mechanical advance unit, although our guess is you’ll never need or want to revert back to points. 

Importantly, our subject R75/5 has never run better, with quicker starting and absolutely solid performance across the rev range. 

As always, we recommend having a good shop manual on hand for parts identification and proper torque specs.

1. Disconnect the negative lead to the battery. Disconnect the fuel lines and remove the gas tank. Remove the three 5mm Allen head bolts securing the front cover, then remove the cover.

2. Remove the 10mm nut securing the mechanical advance unit. Remove the advance unit and replace the nut, being careful not to over-tighten it. You can leave the points in place as a backup; they’ll no longer be actuated.

3. Since we left the points in place, we also left the wiring to the points in place. The points must be taken out of circuit, however, so we disconnected the points grounding lead at the right hand ignition coil, leaving the wire accessible.

4. Next, remove the 6mm Allen head bolt securing the alternator rotor. It will usually break free with a sharp rap on a socket handle. If not, put the bike in gear and lock the rear brake.

5. Replace the original washer on the alternator Allen bolt with the washer in the kit. Next, insert the bolt and washer through the trigger wheel hub.

6. Lightly coat the bolt threads with thread locking compound. Install the bolt with the trigger wheel hub. Torque the bolt to 14ft/lb, slightly less than stock owing to reduced thread engagement due to the trigger wheel’s thickness.

7. Remove the two screws securing the alternator wiring connector plate. Note the Y post at left. As the next photo shows, we had to shift the position of its lead to make room for the sensor.

8. Put the sensor assembly in place on top of the connector plate. Using the two Allen head bolts with washers included in the kit, secure the sensor assembly and connector plate. 

9. Next, slip the trigger wheel in place over the trigger wheel hub, centering the disc in the black sensor pickup slot. Lightly tighten the two small Allen head screws to secure the trigger wheel. The exact position of the trigger wheel will be set later.

10. Route the sensor harness to and through the top of the front cover. We cut a small relief in the grommet for the charging wires, making sure the sensor harness wouldn’t be crimped by the cover once installed.

11. The kit includes three separate wires; brown wire for ground, black wire to ignition coil negative terminal, red wire to ignition positive power supply. With a soldering iron, tin one end of each wire. This ensures a positive connection when connected to the module plug.

12. Following the manual instructions, install the wires as shown in the module plug and secure the clamping screws. From left to right: red ignition power supply wire; small white sensor unit wire; small yellow sensor unit wire; small brown sensor unit wire; brown ground wire; black negative coil wire.

13. Using the included hook-and-loop material, mount the module under the rear of the top frame tube, toward the seat. Secure with the included zip ties. Plug the harness into the module and zip tie the wires together.

14. We needed an additional spade terminal on the positive side of the left coil for the red power lead to the module so we added a terminal from an old coil, then connected the red power lead after crimping on one of the supplied spade connectors.

15. Next, crimp one of the supplied spade connectors onto the black lead from the control module and connect it to the negative terminal on the right coil. 

16. Crimp one of the supplied ring connectors to the brown ground wire from the module. We secured the ground wire at the front mount of the left coil, pairing it with factory ground wires already located there.

17. Set the engine at top dead center, “OT” on the flywheel. Reconnect the battery. Turn the ignition on. Loosen the trigger wheel. Rotate the trigger wheel clockwise until the red LED on the sensor lights. Continue slowly until the trigger wheel opening passes the sensor and just turns off the LED. Lock the trigger wheel set screws in place.

18. Start the engine. Using a timing light, check ignition timing at idle and full advance. We were spot on, requiring no further adjustment. Remove the trigger wheel set screws one at a time, coat with thread locking compound and reinstall. Disconnect the battery. Reinstall the front cover. Install the gas tank and reconnect the battery. Go ride.

Replace Honda CB450 Swingarm Bushings

Honda CB450 swingarm bushings have a reputation for wearing out prematurely. Early CB450s like our subject 1970 CB450K4 used metallic bushings, while later ones apparently switched to plastic, a material more than a few manufacturers embraced for ease of installation.

Whether early or late, CB450 swingarm bushings don’t appear to last more than 10,000 miles or so. Our subject bike doesn’t appear to have led a particularly difficult life, yet with a mere 13,000 miles showing on the clock the swingarm bushings were shot, exhibiting an easy 1/8 inch or more of slop on the swingarm pivot pin. Although a small amount of play won’t show adverse effects, too much results in a wandering rear end, the back wheel moving left and right, generating an uncontrollable steering input. Typically, once the wear becomes great enough to notice, it accelerates rapidly.

As originally fitted, the swingarm on the CB450 (and many other Hondas, including the CB500T, CB500 and CB550 Four and all pre-1979 CB750s) had a single bushing on either side of the swingarm followed by a felt sealing washer, a thrust bushing and an outer metal dust cap. Original replacement bushings are still available, but experience shows that if you’re actually riding your bike you’re wise to consider fitting aftermarket bronze bushings like the ones we sourced from Honda specialists Charlie’s Place.

The bronze bushings from Charlie’s Place do away with the felt sealing washers and the thrust bushings, and at $70 a set they are only marginally more expensive than stock (typically around $55-$65 for bushings, thrust bushings and felts), and thanks to their superior material it’s unlikely you’ll ever replace them again. BikeMaster

Better yet, the bronze bushings are very easy to install. The factory bushings have no shoulder, requiring the installer to ensure they’re properly inserted to the correct depth inside the swingarm. The bronze replacement bushings are shouldered, making insertion installation much easier: Just press them in until they seat.

While installation is easy, the old bushings can be difficult to remove, particularly the early metallic style, which can become seemingly welded to the swingarm. The solution is often to cut them out or press them out with a hydraulic press, if available. Thankfully, ours removed quite easily using nothing more than a hammer and a blunt punch.

As we show, installation is a snap, but you might have to give the bushings a quick pass with a small brake cylinder hone to get a proper fit for the swingarm pivot. The bushings are a light interference fit with the swingarm, so they tend to compress slightly. If you have to hone them, do so in short passes, checking the fit of the swingarm pivot pin frequently. You don’t want to remove any more material than necessary for the pin to slide into place.

This is a fairly straightforward job, easily within reach of the average weekend mechanic. The only special tools you might need are a small 3/4-inch to 2-inch brake cylinder hone and a torque wrench for final tightening. Budget a morning to get the job done, and as always, we recommend having a good shop manual on hand for parts identification and proper torque specs.

 

1. Put the bike on its centerstand. Disconnect the chain. Disconnect the brake stay at the brake hub. Disconnect the rear brake actuating rod. Remove the rear axle cotter pin, loosen the axle nut and then remove the rear axle and finally the rear wheel. Remove both lower shock absorber mounting bolts.

2. Remove the swingarm pivot bolt nut on the left side of the swingarm.

3. The end of the swingarm pivot bolt is dimpled. Using a suitably sized punch, gently knock the pivot bolt through the swingarm. Remove the bolt.

4. With the pivot bolt removed, pull the swingarm straight back and free of the frame. To give ourselves a little more working room, we removed the left shock. Although we didn’t, removing the chain guard simplifies chain installation.

5. Once the swingarm is free, remove the dust caps and thrust washers (thrust washer pictured). Set the thrust washers aside; you won’t use them with the new bronze bushings.

6. Next, using a suitable drift, remove the swingarm pivot pin. It should knock out easily, but accumulated grease, dirt and corrosion can make it a little stubborn to remove.

7. Here’s our pivot pin after knocking it out of the swingarm. Thankfully, it cleaned up well, as replacements are getting quite difficult to find.

8. With the pivot pin knocked free, remove the felt sealing washers at either end of the swingarm and discard them. The new bronze bushings don’t use these.

9. Next, remove the old bushings. Ours pushed out fairly easily using nothing more than a blunt-ended punch and a hammer, but they are known to be difficult to remove, sometimes requiring a hydraulic press to push them out or a hacksaw blade to cut them out.

10. Here’s one of our old bushings removed from the swingarm. Before moving on to installing the new bushings, clean any debris or grease from the inside of the swingarm tube.

11. Next, install the new bushings. We pressed them in using a simple homemade tool made up of a piece of all-thread rod, with washers and nuts at each end, steadily tightening the nuts until the shoulders of the bushings seated against the swingarm.

12. Here’s one of the bushings fully seated in the swingarm. With the new bushings installed, we found the swingarm pivot pin to be a tight fit.

13. To make the swingarm pin a sliding fit in the bushings, we lightly honed them with a small brake cylinder hone, removing only enough material to allow a tight sliding fit. After honing, thoroughly clean the bushings with brake parts cleaner.

14. With the bushings honed, our swingarm pivot pin (visible inside the bushing) slipped into place. With the pivot pin installed, lightly grease the dust caps and install them on either side.

15. Using a grease gun, push the old grease out of the swingarm pivot bolt until only fresh grease comes out of the lubricating holes in the bolt.

16. Push the swingarm back into place in the frame, then insert the swingarm pivot bolt through the swingarm from the right side.

17. With the swingarm pivot bolt in place, thread the pivot bolt nut onto the bolt and then torque it to 51-65ft/lb. We went for the middle of the range, 58ft/lb.

18. Next, using a grease gun, grease the swingarm pivot until fresh grease just starts to show around the dust caps. Reinstall the rear wheel, the drive chain, the brake stay and the brake linkage. Adjust the chain as necessary and tighten the axle nut, making sure to reinstall the cotter pin.







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