Rider: Eric Tucker #22
1965 BSA 350cc Model B40 "Star”

Modified for Motocross Competition
Owned and Raced 1978-1998 by Eric Tucker

Sponsored by West Coast British Racing, Livermore, CA.

BSA (Birmingham Small Arms) originally made rifles and bicycles for the British army, and produced motorcycles from 1911 until 1971. During the 50's they were the world's largest motorcycle manufacturer. The model displayed here was produced from 1960 through 1970. A similar, factory special model won world motocross championships in 1964 and 1965 ridden by motocross legend Jeff Smith.

This motorcycle was raced by Eric Tucker in California Vintage Racing Group (CVRG), American Historic Racing Motorcycle Association (AHRMA) and Texas Vintage Racing Club (TVRC) motocross events since 1985.  In 1991 and 1992 with the B40 (350cc) engine, it won the AHRMA Western Regional Championship series in the intermediate level 500cc Premier (1965 and earlier) class.

WCBR-B40 was a fun project. Built in 1990 to replace the aging C15 (250) engine in the #22 machine (ridden by Eric Tucker), the B40 would prove to be very competitive in the Premier Class (500cc).

Under CVRG/AHRMA rules "all modifications must be period"; meaning: an early B40 can compete in the Premier 500 class (pre-65), while a later Square B40 has to compete in Classic 500 (post-65 to 70). With that in mind we began with a Round Barrel B40 engine. We had two things in mind; More BHP and strengthen the gearbox. With our own blue-print in had we put the cases into the mill and moved the output bearing hole .250" outwards, then bored the L/S bushing hole to take a needle...  a B44 gear set was then fitted.
The crank was lightened (alot!), and then re-balanced to suit. The inside of the cases were polished, as was the outside. A custom MegaCycle cam and B40SS followers were fitted. A B44 alloy cylinder was shortened to suit the B40 engine; a 9.5:1 Hepolite was fitted. The head was ported/polished and big valves fitted. A special intake manifold held a 932 Amal. Primary was all lightened and alloy clutch fitted. 428 sprockets/chain was used on the final drive.
Ignition was stock points with a MityMax battery eliminator.
The engine had great power, rev'ed to the moon (for a B40), and throttle response was:
"twist the throttle and the rear tire reacted immediately!" said WCBRs Michael Green after testing.
Best of all it was both FAST and dependable!

Even after this machine was later sold, it still continued to win races in the Premier class!
Above:This photo shows Eric Tucker taking practice laps on his B40 in its first outing in March 1990 at Glen Helen Park near San Bernardino, CA. In this guise it had a substantially stock B40 road-going motor, prior to its substantial upgrading into a right firebreather by WCBR for the following season. Despite the relatively mild tune of the high-mileage motor here it acquitted itself and its rider quite well, finishing second in its class in both motos behind Fred Mork on his 500cc ESO, having very nearly overtaken Fred at the finish of the second moto – just missing a first–place trophy. The right arm and left foot seen behind Eric in this photo belong to none other than Dick  Mann, steering his ultra-sanitary 500cc TriBSA. Eric admits, "Had the photo been taken two seconds later it would have been a picture of my right arm and left foot trailing Dick’s bike."
B40 at Fernley, NV 1991, now with Premier yellow # plates.
: Eric and the B40 hard at work, 1992 Fernley, NV.
Right: Eric finishes the 1992 Mud-Fest at Sandhill Ranch during the AHRMA National MX.
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