loudbike.blogs.com > Adam Bennett's 350 Aermacchi Sprint Racer

Introduction

Adam Bennett and I built this racer about 3 years ago.. Well, truthfully - I started the project, tore my ACL the year that it was to be developed, and he picked up the ball and ran with it.

I had been suffering Fran McDemott's constant badgering regarding the delight and simplicity of singles and "why in the world haven't I built one yet?" - and sampled Shannon's Sprint a few times at Mosport - so when I caught wind of a tired but mostly complete Sprint racer, I bit the bullet and dropped the cash. The bike was based on a Sprint SX (a dual-purpose version that weighed a ton), but it came with a spare '60's 250 frame and an interesting collection of spares. Adam had a taste of Mosport earlier in the prior year on his GSXR, and although I could ride the GT and the Loud Bike (barely) with the injured knee, there was no way I could bend the knee enough to ride the Sprint. Adam cheerfully set off in the rain and blasted around oblivious to leaky rear shocks that gave up their dampning benefit after about 6 laps. The hook was set.

Later that weekend, Shannon came in after a session on the bike claiming "My butt is on fire!". Sha hadn't really learned how to communicate mechanical symptoms very well at that stage in her development so we sent her back out with the reassurance that "they always vibrate like that". Less than 3 laps later, she was back in and I got on the bike to run it up the pits a bit. When I applied throttle, it felt like the crankshaft was going to bounce itself through the cases. We could pull the end of the crank about 1mm out just by yanking on the end of it, so the bike was parked. So began a massive rebuild that spanned almost 10 months.

In it's brief history, the rebuilt bike carried Adam to Rookie of the Year, at least five class championships (I stopped counting) and the VRRA #1 plate in 2003. It also was awarded “Showing Excellence in Vintage Road Racing” by the North America International Motorcycle SUPERSHOW 2004 and distracted by his new 125RS Honda, he only managed to fininsh in fifth and second place respectively in the final Period 1 and Pre-65 2004 standings. (Of course, he cleaned up in the 125 class on his new toy.)

Specification:

Frame: 65' Aermacchi / H-D Sprint 250 seriously modified with additional bracing to the swingarm mounts. H-D Sprint 350SX swingarm running in beefed-up brackets with thrust washers instead of bushings.

Engine: '70 base, '73 top-end, '73 5-speed gearbox. Aermacchi Northwest supplied close ratio gearbox conversion, modified crank pin and JE light weight racing piston, nimonic race valves complete with double race springs and titanium caps and keepers, and N6 race cam. Adam adapted a Dyna ignition to provide spark and the bike runs a 36mm Dellorto carb.

Rolling Chassis: H-D Sprint 350SX rear wheel, Aront rims, stainless spokes, Ceriani aluminium body shocks, one-off header with Aermacchi Northwest megga, Dyna coil, Ducati 900SS seat, modified (with a blackjack) Aermacchi Sprint 350 tank, custom-made (by Adam) rearsets, modified early TZ350 fairing, stunning CNC clip-ons of unknown origin, Betor 35mm forks, early Honda 350 front brake and hub with Ferodo's finest vintage racing compound shoes, custom-mounted Ceriani sterring damper.