How to Dyno Tune a Motorcycle

by Lina Schofield

A dynojet is a machine used to diagnose various driving issues in motorcycles, such as improperly installed jet kits, running problems related to carburetors or throttle bodies that aren't synchronized correctly, incorrect cam timing and improperly mapped fuel injection systems. Dyno tuning is the process of tuning the motorcycle using the dynojet. A dynojet works by calculating the amount of time it takes to accelerate a heavy steel drum through one full revolution.

Loading the Motorcycle into the Dyno Room

Drive the motorcycle into the dyno room. Inspect your motorcycle for leaking oil, fluids or coolant. Look for any loose parts. Check all fluid levels, tire pressure and tread condition. Examine the clutch and chain adjustment rate.

Push the motorcycle onto the dynojet test cell, placing the front wheel in the cradle. Strap the front wheel down with wheel straps. Align the rear axle on the dyno drum by sliding the rear cradle advance. Use the dynojet starter motor to align the motorcycle on the drum by tapping the "Start" button.

Attach soft, tie-down straps to the motorcycle frame. Position the straps to allow adequate clearance for the brake pedal, shift lever and exhaust system. Sit on the motorcycle and pull the slack from the straps.

Connect the inductive tach pickup on the dynojet to spark plug wire #1 on the motorcycle.

Roll-on Testing

Check the torque and horsepower output by performing a roll-on test. Start the motorcycle in first gear and push the "Start" button on the dynojet to get the drum rolling.

Shift through the gears at a steady throttle opening until you reach fourth gear. Disengage the gas and push the remote sampling button on the dynojet control panel and begin testing.

Snap the throttle full open in fourth gear and accelerate the motorcycle until the tachometer reaches the red line. Release the throttle. Allow the engine to decelerate with the clutch engaged.

Slow the motorcycle down by pushing on the dyno brake. Evaluate the printout data.

All-gear Testing

Perform an all-gear test to check the motorcycle fueling at variable throttle settings. Warm up the engine. Put the transmission into first gear and start the drum on the dyno jet.

Shift into second gear. Push the remote sampling button on the dynojet control panel. Snap the throttle wide open and accelerate the motorcycle to your preferred shift point.

Shift through the gears at the same RPM measured and shown on the tachometer.

Accelerate to the top gear then close the throttle. Press the remote sampling button to complete the test.

Allow the engine to decelerate with the clutch engaged. Slow the motorcycle down by pushing on the dyno brake. Evaluate the printout data.

Items you will need

References

About the Author

Lina Schofield began writing professionally in 2005. She is a professional freelance writer who has worked on a variety of projects, including the founding of the quarterly publication "Propaganda." Schofield also has been published in several student collections. She received her Bachelor of Arts in English at University of Wales Trinity Carmarthen.

Photo Credits

  • photo_camera motorcycle image by Bionic Media from Fotolia.com