Building the Henning Honda CB500
When Motorcycle Online heard that racer Todd Henning and Kinetic Analysis' master tuner Kenny Augustine had joined forces to build an American Historic Racing Motorcycle Association (AHRMA)-legal Honda CB450, we smelled victory in the making and decided to get a scoop on the story by volunteering one of our editors -- resident Gearhead Aaron Cooley -- to help out one late night the week before Daytona. The pair worked for about 10 hours, flattening cylinders and test fitting parts on old Honda 450s. In exchange for Cooley's help, Augustine gave us a tuner's eye view of exactly went into the world's fastest vintage Honda CB450. At first, a vintage Honda twin might seem to be a bike destined for perennial back-marker status, especailly when competing against high-dollar classics such as Nortons and MV Augustas, but in reality the 450 powerplant has only a few minor design flaws -- and in the eyes of Augustine is the best choice for the class.
Why a 450 Honda?
One obvious advantage is availability. The engine from a vintage Triumph might run you 3000 bucks just for a basket case engine, but you can easily locate and purchase several 450 Honda engines for a fraction of that price, but the crucial difference is that new parts are still available from the Honda.
A second advantage is the motor's potential. Stock, the Honda CB450 engine may not make as much power as a Norton Manx, but the basics are all there: The head and cylinders are well cooled because the engine is inline, meaning both cylinders are directly exposed to cool airflow. There are four total valves rather than two (Manxes are single-cylinder machines), which gives better intake. Lastly and most imporantly, given equal displacement, equal engine height, and equal peak piston velocities, a twin will be turning higher rpms than a single. Higher revs, as every tuner knows, means more fuel combusted per second, and that means more power.
Now, you're probably wondering why nobody has ever won before with a Honda -- either in modern-day AHRMA racing or the GPs of old -- and the reason is this: Stock, the bike doesn't even come close to it's competition. In other words, it sucks. The engine has to be highly modified to unlock its basic potential. So far, Kenny Augustine is the only tuner with the right combination.
Stock, the bike doesn't even come close to it's competition. In other words, it sucks.
Augustine attributes his success with Todd Henning's bike to several things, first of which is Henning himself. "He's very bright, he's very articulate, he's very perceptive, he's very through, and he's got a lot of follow through." Henning gave Augustine permission to do what ever needed to be done to make the motor faster. That allowed Augustine to build the motor without limitations on what was to be modified.
"You need a little bit of experience, and a ton of commitment. If it needs an X, you build an X. If it needs a Y you build a Y. You have to be willing to build what the motor needs rather than just what you feel like."
The job of changing those parts, however, is no less complicated. Some might even say it's more complicatedsince anything on the engine itself that can be seen from the outside must come from a stock Honda street engine, where as a modern superbike is designed from top to bottom for racing. Most of the superbike engine can be modified to suit the needs of the individual, with few limitations, by the factory. The Henning Honda, however, has to work basically the same way as any Vintage Honda CB450 would work; no wet sump, no liquid cooling, no ram-air systems, no side cam drives, no forward leaning cylinders, no sloped intake and exhaust paths.
The result of all this work? Todd Henning is off to an excellent start, winning the 500 Sportsman Premier at Daytona, and is looking forward to an excellent season.So what did Kenny Augustine do to turn a (already) race-preped Honda CB450 engine into one that could win at Daytona '95? In short, almost everything from the cylinders up was modified. (Click here for the full details, with pictures.) That may seem like a lot of work, but Kenny left parts unchanged than most 750s prepared for AMA superbike competition.
Todd Henning has chapped a few hides by winning a class which is supposed to give the advantage to the AHRMA's treasured European classics, but don't be fooled by his bike's easy-to-attain exterior. Henning has put as much work into building and attaining parts for his bike as any of the others lining up on the starting grid.
The result of all this work? Todd Henning is off to an excellent start, winning the 500 Sportsman Premier at Daytona, and is looking forward to an excellent season. Who will be wearing the number one plate come Daytona '96 (AHRMA's season-opener) remains to be seen, but knowing what is going in his powerplant, our money is on Todd to bring home the Championship.
If your interested in owning a Todd Henning vintage Honda racer, parts and complete bikes can be had. Contact Henning at (508) 487- 1140.
If you interested in tuning services for vintage racers, or high quality tuning of any kind, you can contact Kenny Augustine at Kinetic Analysis in California, (415) 499-1458.