Denis started his racing with a stock Honda 450 that ran the Quarter Mile in 12.12 or 128mph normally aspirated. When he added a supercharger he reduced the time to 11.80 or 130mph. Denis took the bike to Bonneville and ran it but the blower injected salt and hurt the motor.
Denis used many of the parts from the Suzuki and constructed the Harley- Davidson powered streamliner. This streamliner had center-hub steering and a true monocoque frame. The bike was powered by a Harley-Davidson Sportster 83in running on 70% Nitro-methane.
The Streamliner broke the world record at 265.492mph with Cal Rayborn as the rider. When the bike made it's record runs the engine was a Warner Riley- Sporster HD engine with tuning from S & S' George Smith Sr. It was immortalized in the 1971 film 'On Any Sunday' and is now owned by the Indianapolis Motor Speedway Museum in Indiana.
The Triumph streamliner was design from the ground up using wind tunnel data from the Cal Tech. The bike was originality going to be Harley-Davidson powered but the bike was powered by two 750 Triumphs. The transmission was originally a Triumph but due to transmissions exploding they switched to a Harley-Davidson transmission. Boris Murray rode the bike to 272mph under FIM & AMA private time. The machine was never able to make a return run and thus not getting the record. The bike was eventually destroyed in a crash. It still holds the title for the fastest Triumph powered motorcycle (one way pass).
The Norton was a rebuild of the Triumph with 2x 800cc Norton's running on 92% Nitro-Methane. The motors were prone to detonation and the machine didn't progress further. This bike was recently found in Germany and restored and will be housed at the Birmingham Museum in England. This streamliner also holds the record for fastest Norton powered motorcycle (one way pass)
This machine used the same body design from the previous streamliners. The bike was powered by an S & S 115ci engine running 95% Nitro-Metane with a Nitros kit. Rider Dan Kinsey was able to reach a speed of 286mph but didn't reach the record. The bike is now housed in the S & S Cycles collection in Viola, Wisconsin. It remains the fastest single engine Harley-Davidson based motorcycle.
Denis had always wanted to design his own motor and transmission to bypass the problem he had with stock motors. Tenacious II was the first motor to use the BUB V4 and transmission. The front suspension was a custom girder type front end and a fully suspended rear. Rider Rocky Robinson was able to reach 297mph in 2001 at Lake Gairdner in Australia. Racing stopped when the engine threw a rod and the team was having problems with high speed handling. It is still the fastest motorcycle south of the equator.
The results from this chassis design led to the complete redesign of the shape of the motorcycle .