Motorcycle: Racers - Aermacchi Ohv Racers 1961 - 1978
Date: Sunday, October 31 @ 15:22:42 UTC
Topic: Motorcycle, Motorcycles, Motor Cycle
Aermacchi Ohv Racers 1961 - 1978
Originally an aircraft factory - hence the name — Aermacchi diversified into motorcycle production in 1948, in Varese, Italy. Its first models were 123cc (7.5cu in) singles - two-strokes but already possessing the horizontal cylinder which was to become so typical of the marque. Overhead valve four-stroke singles followed, both road bikes and the potent Ala D'Oro (Golden Wing) production racer. A generation of elegant racing models were developed from the late 1950s onwards, based on this Alfredo Bianchi-designed machine.
Although the racers were built in both 250cc (15cu in) and 350cc (21cu in) versions, it was the latter which achieved the greater success. Even during the 1960s, a single-cylinder push-rod machine was an anachronism among the exotica then crowding the grands prix grids, yet the "Macchi" exploited its fine handling, light weight and slim aerodynamic profile to the fullest. Its best world-championship performance came in 1966 when the late Renzo Pasolini — the "Paso" in the Ducati model of the same name - took third place in the 350cc grand prix championship.
It was as a privateer mount that the little "Macchi" achieved its greatest popularity and success however, although it also had a reputation for being temperamental unless expertly set up. Perhaps its most remarkable performance came in the 1970 Isle of Man TT races when Alan Barnett lapped the daunting Mountain Course at a stunning 99.32mph (159.84kph) on a Syd Lawton 350, recording well over 40mpg (15km/litre) in the process.
Nor were the ohv single's exploits confined to the track. On 21 October 1965, a 250cc Aermacchi established a world mile record of 176.817mph (284.55kph) and kilometre record of 285.21kph (177.225mph) at Utah's Bonneville salt flats. Although nominally a Sprint roadster, the machine in question used a 1966-specification CR racing engine on standard pump fuel. Officially, Milwaukee dubbed its Italian singles CR, CRS and CRTT, although in Europe these designations were largely ignored. The single was produced with many variations over the years, but the 350's typical power output was around 38bhp at 8,400rpm. Bore and stroke were under-square at 74 x 80mm, although incurred a dangerously high piston speed (almost 4,400ft/!,340m) at maximum revs. As a result, other configurations were also built, including short stroke and ultra-short stroke examples. Compression was high — around 11.4:1 — and the engine breathed through a 35mm dell'Orto carburettor tipped almost vertically to feed fuel into the horizontal cylinder. A short megaphone exhaust swept down the right side of the machine. The racer was available with a choice of "A" or "B" gear clusters, the latter offering the closer ratios, although the engine delivered a reasonable spread of power considering its high state of tune.
The chassis was simple in the extreme, using a large-diameter tubular steel spine, which was reputed to flex but in a controlled, user-friendly way which gave the rider ample feedback.
A variety of suspension and brake components were employed, invariably with telescopic forks (usually Ceriani), twin rear shock absorbers and drum brakes. On later versions, the front drum was often twin-sided.
A measure of the machine's excellence is the sheer joy — and speed — with which many contest classic races today.
Engine: ohv horizontal single
Capacity: 344cc (2 leu in)
Weight: 2451bs (111kg)
Wheelbase: not known
Top Speed: 130mph (210kph)
This article comes from Free Vin Check, Get Vehicle History Report, Free Car History, Used Car History, Auto History, Free Vehicle History, VIN Number Check, Car History, Lemon, Check
The URL for this story is: