Honda XR400R Javascript Gearing Calculator
John's Amazon Motorcycle Book Links
Primary Gear
Front Sprocket
Rear Sprocket
Rear Wheel Dia
1 Gear
MPH
2 Gear
MPH
3 Gear
MPH
4 Gear
MPH
5 Gear
MPH
6 Gear
MPH
RPM
Default values are for a 1996/7/8 or 1999 XR400R.
The XR400R RPM range is up to 9,200 RPM before the rev limiter cuts in - need to double check that?
Realistic dyno runs show 8 to 8,300 as being the max working RPM, unless engine work is carried out to obtain more revs.
Wheel diameter can vary subject to tyre choice. Measure roll circ and use C=Pi times D to calculate, where Pi is 22/7
HRC kit Primary Gears are 24/64 or 2.666 to 1 ratio.
To return the script default values use refresh in your browser plus the control key.
My article on gearing and the XR400 both dirt and Supermoto
is here
Return to The XR4 FAQ
Version last updated Wednesday 6th January 1999. John Rushworth.
John.Rushworth.com
