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Dirt-Bike Designs

Moto Tassinari, a West Lebanon, N.H., company, is a leader in reed valve technology. Two 190/290 teams worked on different projects for the company's dirt bike.

Backflow-Restricting Throttle Body for Dirt Bike Engines

Team: Adams D. Baker '06, Tim Monahan (M.E.M. candidate)
Advisor: John P. Collier
Sponsor: Moto Tassinari, West Lebanon, N.H.

Exhaust backflow robs high performance engines of low RPM power. Our project was to design a backflow elimination device that would restore the lost low RPM power to high performance engines without sacrificing the high RPM performance. While the prototypes were able to improve low RPM power, they could not out-perform a less aggressively tuned engine. Over the course of the project, we investigated ways to measure backflow, determined the effects of reed valves on intake tuning, and developed a series of backflow elimination prototypes. Finally, we gave our sponsor, Moto Tassinari, recommendations for the next round of prototypes.

Tim and throttle
Tim Monahan works on the throttle

how it all fits together
How it all fits together

Design of a Compact Steering Damper for Dirt Bikes

Team: Apurva Nair (M.E.M. candidate), Karl Johnson '06 B.E.'07
Advisor: Benoit Cushman-Roisin
Sponsor: Moto Tassinari, West Lebanon, N.H.

The use of a steering damper in dirt bikes greatly reduces the uncontrollable steering response called headshake that often results in the dismount of the rider. However, this device is not often used in motocross racing. To suit a damper for motocross use, the weight and obtrusiveness need to be minimized with the durability maximized. By using a rotational fluid damper located within the steering column of the dirt bike, these characteristics were achieved. A prototype was built and installed on a KTM 250 EX. The manufacturing techniques used, however, must be refined before the product can be produced commercially.

team
(L to R) John Malanga, Apurva Nair, Karl Johnson