- Nov 17, 2010
Am pretty sure the limit for sidecars was 1,000cc when Chris Vincent raced, so he wasn't breaking any rules in the open sidecar class. The world championship sidecars were limited to 500cc & the BSA of that size wasn't very competitive against the BMW's. I raced a sidecar briefly around that time & all the 'fast boys' in British sidecar racing had BSA A65 engines that were over 800cc. Most used A65 engines fitted with A75 barrels which were a larger bore and modified A10 cranks which gave a longer stroke. The A75 was only sold in the USA but several sidecar racers worked at BSA so had the opportunity to obtain the A75 barrels.