1967 Aermacchi 250 Ala Verde
Number built: N/A
Engine: 248cc OHV air-cooled single
Bore x Stroke: 72mm x 61mm
Output: 21hp @ 7,250rpm
Carburetion: Single Dell’Orto 24mm
Transmission: Helical gear primary, wet multiplate clutch, 5-speed
Ignition: 6v generator, coil and breaker points ignition
Final drive: Chain
Suspension: Telescopic fork front, dual shocks rear
Frame/wheelbase: Tubular steel spine/52in (1,321mm)
Tires: 2.5 x 17in front, 3 x 17in rear
Brakes: 7in (178mm) SLS drum front and rear
Weight (dry): 247lb (112kg)
Seat height: 29in (736.6mm)
Fuel capacity: 4gal (15.1ltr)
1967 Aermacchi 250SS/CRTT café racer
Number built: 250SS: 7,000 (1967), CRTT: 35 (1967)
Engine: 293cc (stock 248cc) OHV, air-cooled single
Bore x Stroke: 72mm x 72mm
Compression: N/A (Stock CRTT: 11:1)
Carburetion: Single Mikuni (Stock CRTT: Dell’Orto 30mm)
Transmission: Straight-cut gear primary, dry clutch, 5-speed
Ignition: 6v generator (none stock), magneto ignition
Final drive: Chain
Suspension: Ceriani telescopic fork, dual shocks rear
Frame/wheelbase: Tubular steel spine/52in (1,321mm)
Tires: 100/90 x 18in front, 110/90 x 18in rear
Brakes: Oldani 8in (203.2mm) TLS drum front, 7in (178mm) SLS rear
Weight (dry): N/A
Seat height: N/A
Fuel capacity: 4gal (15.1ltr)
Stop me if you’ve heard this one before: Italian aircraft manufacturer, banned from building planes after World War II, decides to focus on two-wheeled transportation. Sound familiar? You could choose from, among others: Piaggio (Vespa), MV Agusta or Aeronautica Macchi.
Giulio Macchi’s company built some of the world’s fastest aircraft in the interwar years and during World War II. In 1934, the Macchi MC72 set an absolute world record speed of 440.7mph that held for five years, and is still the fastest speed ever achieved by a propeller-driven seaplane.
Much like Honda, Aermacchi had a Dream. On joining the company in 1956, chief designer Alfredo Bianchi was tasked with creating an all-new production motorcycle. Bianchi borrowed styling ideas from the automobile industry to produce a futuristic-looking motorcycle with fully enclosed bodywork that hid the mechanical components. These included a compact, lightweight 175cc 4-stroke engine and an ingenious swingarm rear suspension controlled by a single spring/shock unit.
While the Chimera (Italian for “dream”) created a sensation at the 1956 Milan show and was well received by the motorcycle press, it failed to impress potential buyers, and was an abject commercial failure (see Motorcycle Classics, March/April 2014).
Under considerable pressure from Aermacchi management, Bianchi needed a new design in a hurry. For expediency, he decided to keep the Chimera’s spine frame (modified for dual rear shocks), its powertrain and running gear. He discarded the controversial bodywork and adopted contemporary Italian sport motorcycle styling, adding some touches of his own. The result was the 1958 Ala Bianca (white wing) and Ala Rossa (red wing).
Both retained the Chimera’s 175cc overhead valve 4-stroke, 4-speed unit-construction powerplant with its characteristic near-horizontal cylinder and vertically split cases. The light alloy cylinder head capped a cast-iron barrel of 60mm bore. The built-up crankshaft ran on a roller bearing big end and had a stroke of 61mm for 172.4cc. A gear pump circulated oil from the wet sump, and drive to the wet multiplate clutch was by helical gears. A 4-speed gearbox drove the rear wheel by chain. Feeding the 6-volt lighting circuit and providing sparks was a crankshaft-mounted generator.
The Ala Bianca used an 18mm Dell’Orto UB-series carburetor for 9.4 horsepower at 6,500rpm, while the Ala Rossa featured higher 9:1 compression and a 22mm Dell’Orto for 13 horsepower at 6,700rpm. The rest of the running gear was borrowed from the Chimera, including its 17-inch wheels running on 2.5-inch front and 2.75-inch rear tires, and full-width alloy drum brakes. This gave the Ala Rossa a respectable top speed of around 76mph, a competitive performance in Italy’s important 175cc sport bike class.
Within a year the Ala Rossa was joined by a 250cc version, the Ala Verde. It was identical in most respects to the 175 except for bore and stroke of 66mm x 72mm for 246cc and a wider 3-inch rear tire. With 8.5:1 compression and a 24mm Dell’Orto, the Ala Verde produced 18 horsepower at 6,700rpm, good for a top speed of 82mph. A touring version of the 250, the Ala Azzurra, with a smaller carburetor and lower compression, was also available.
At the same time, the factory also produced what were essentially race-ready editions of the 175 and 250 bikes with the name Ala d’Oro, or gold wing. The 250 version used 10.2:1 compression and a remote-float 30mm Dell’Orto SS1 to produce 25 horsepower at 9,000rpm. Straight-cut gears replaced the helical primary drive of the street bikes, and the ignition was total loss. Brakes were upgraded to Oldani twin-leading-shoe front and single-leading-shoe rear with magnesium hubs. Weighing just 225 pounds, the 250 Ala d’Oro claimed a top speed of 110mph.
Aermacchi singles turned out to be very competitive in production racing in 175cc classes in continental Europe and in the 250cc class in Britain. Their overhead valve engine technology may have seemed pedestrian for a race bike, but provided the benefit of simplicity without giving away too much performance to more sophisticated machines. The rigid spine frame also lent the Ala d’Oro and Ala Verde superior handling and light weight. Though not as reliable as they might have been, the Aermacchis racked up some notable results. Perhaps their most impressive performance was in the 1964 Manx Grand Prix 250cc class, when four of the first six bikes home were Aermacchis.
By this time, though, it was clear some development was required, especially for the race bikes: a bigger bore and shorter stroke (72mm x 61mm) gave 248cc; an alloy cylinder replaced the iron item; the big end bearing became a double roller; the transmission gained one gear to make five; the camshaft ran on needle roller bearings; and the clutch was converted to run dry, making the race bikes easier to push-start — Le Mans style!
Now with much better reliability, the “dry clutch” 250s continued to be competitive in Europe, while another engine stretch to 344cc (74mm x 80mm) produced a potent competitor in 350cc GP racing. Renzo “Paso” Pasolini finished third in the 350cc Grand Prix world championship in 1966, with Kel Carruthers repeating that achievement in 1968 behind the multi-cylinder might of Honda, Benelli and MV Agusta.
The 350 performed particularly well in the Isle of Man Junior TT, placing sixth in 1965, fourth, fifth and sixth in 1967, fourth and sixth in 1968, and with four machines finishing in the top ten in 1969! The Aermacchi 350 has remained popular in historic club racing to this day.
Aermacchi produced limited numbers of race-tuned machines for U.S. flat track and road racing, designated CR and CRTT, respectively. These borrowed engine technology from the Ala d’Oro racers, both the long-stroke and (later) short-stroke versions. They were especially popular in AMA Grand National championship racing, which included both dirt track and tarmac races. Apparently, the CR was never supplied complete from Italy, the rigid-rear frame being built in the U.S. Notable riders who developed their careers on CR/TTs included Cal Rayborn and Gene Romero.
Also developed for the U.S. market was a motocross machine, the CRS, usually fitted with a 4-speed gear set, presumably more robust in offroad competition.
A dedicated Ducati enthusiast, Mark Haapalainen of Richmond, British Columbia, Canada, hadn’t considered restoring an Aermacchi until a search for a suitable bike from Bologna came up negative.
“I had been searching for a small-bore Italian bike,” Mark says. “Originally, I had wanted to get a smaller Ducati, a 175 or 250, but all the ones I could locate that were in reasonable condition, they were asking too much. And the ones that were reasonably priced were in really rough shape. I then thought about others, and Aermacchis came up.”
Unable to locate a suitable Aermacchi in Canada, Mark eventually found what he was looking for — the basis for a streetable café racer — at Lancaster Aermacchi Sprints in Tampico, Illinois.
Ex-racer Ron Lancaster builds and restores Aermacchis as well as selling parts. Lancaster wasn’t able to provide much background on the Ala Verde he was selling, except that it had come from Ohio and had been a road race bike. It also contained a curious mix of Aermacchi components. The serial number indicated that the engine started out as a 1967 U.S.-market 250cc short-stroke CRTT with the correct magneto ignition, dry clutch, straight cut primary gears and 5-speed transmission.
“It had the CRTT motor,” Mark says. “But curiously it also had the generator as well on the other side.”
As Mark was planning to build a street bike, having the 6-volt generator in place was a bonus. But only the street bikes had a generator. So that pointed to the engine having been built up from parts, or having had major repairs at some time. But as none of the Aermacchi street bikes came with a dry clutch or straight-cut primary gears, it was definitely a race motor.
“Ron was of the opinion that someone had blown up the original motor and had gotten the street bike lower end … because it has the full CRTT top end, including all the valves and valve gear. It has all of the correct camshafts and everything else for the 1966-1967 CRTT-based motors,” Mark says.
It also turned out Mark’s engine had been fitted with the earlier 72mm long-stroke crankshaft. So the most likely explanation is that the short-stroke CRTT engine had been blown up, and the bottom end replaced with an earlier long-stroke crank from a street bike — hence the generator.
“It’s a 72mm stroke crank … but a 72mm piston, which makes it 293cc, not a 250, so it’s a mix of long stroke and short stroke.” The frame that came with Mark’s bike also showed a checkered past: “It was a 1967 250SS-based frame. So that’s another curious thing about it, because it had rearsets on it and a racing alloy fuel tank,” he says.
“What I wanted was a European period-style sports-racer-look bike with clip-ons, but with a headlight and all the lighting. I looked at a lot of photos online trying to get the color and the patterns and everything else,” Mark says.
The decals came from Moto Italia in California, while many other parts including the battery box and toolbox were found at Harley-Davidson dealers across the country, especially in the Midwest, where there seemed to be a network of dealers with older Aermacchi parts. Mark says if he called a dealer looking for parts and they didn’t have what he was looking for, they would always give him a referral.
“They’d say ‘Well, try calling these guys,’ and they would give me phone numbers, and all these names, and I’d call them and they’d be the parts guys at one of these older Harley-Davidson dealerships.”
Once he had most of the required parts, Mark completely dismantled the Ala Verde for blasting and paint, then reassembled it, adding the necessary components for street use.
“I’m very happy with the result,” Mark says. “It looks exactly as I was hoping it would and all of the positive feedback I’ve had is reinforcement of that. I think I hit it pretty close.”
Mark hasn’t yet had the opportunity to ride the Aermacchi: A house move and inclement weather mean the bike has been in storage until now. But he also hopes the Ala Verde will be eligible for the Moto Giro d’California next year.
“That’s still in the background, I think,” Mark says. “That’d be the ultimate, once I get it truly sorted out.” MC
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