Tuning The Rotax 800 Triple Page 3 of 3

Stage 6- Bored Carbs & V-Force Reeds The next step was to increase the airflow, so Rich bored the Mikuni TM-38mm flatslide carbs out. This only resulted in a 1.3 HP gain, up to 176.2 HP @ 8600 rpm. V-Force Reeds, which boosted the power on the stock pipes by 3.6 HP, were re-installed, and the power jumped up to 180.7 HP @ 8600 rpm, a 4.5 HP gain!   Stage 7- Lake Racer Porting Here is the final stage, lake racer porting and head work, raising the compression and requiring 100 octane fuel. We're now up another 4.6 HP at 8600 rpm with a fairly broad torque band of over 113 foot pounds from 8200 to 8600 rpm. This is still using the stock airbox! When the airbox was removed and the carbs jetted up, it made less power, Ski-Doo did an excellent job with their airbox design.   Due to the rev limiter at 8950 rpm, Dyno Port worked very hard on the pipes & porting to let the engine make good power below 8900 rpm in all of these stages. The asphalt engine Rich raced with made 201 HP @ 9500 rpm, but this was a Pro-Stock race engine with bigger carbs, a '98 ignition, and higher rpm race pipes. For more information on any of these modifications contact Dyno Port at (315-258-5618).

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