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trailrider894
01-19-2011, 09:13 PM
Hey, I am working on my re-build, and want to change my sprockets, what sizes should i get for racing MX with a 20" rear tire?

CJM
01-19-2011, 09:24 PM
http://home.earthlink.net/~gellett/400ex.htm change the rpm to 9100 and play around with the values to be sure.

I tried 14/38 and found due to the hotcam II it ran out of steam to much and hit the limiter in 1st and 2nd WAY to much. I also tried 16/39 and if I was doing drags thats what I would keep-tons of topend, I settled on either going back to 15/38 or I did setup but havent ridden much with 15/39.

For me, 15/39 should give me between 14/38 and 15/38.

Also remember, you may have to remove a link or two if you drop sprocket sizes as the chain will be to long.

Remember
* A SMALLER than stock FRONT sprocket will give you more TORQUE.
* A LARGER than stock FRONT sprocket will give you more SPEED.
* A SMALLER than stock REAR sprocket will give you more SPEED.
* A LARGER than stock REAR sprocket will give you more TORQUE.
* By changing 1 tooth on the FRONT sprocket, that is about equivalent
to changing the REAR sprocket 3 teeth.

honda400ex2003
01-20-2011, 07:01 AM
http://i424.photobucket.com/albums/pp325/behemothrocks1999/Just%20Stuff/thumbs-up.jpg

nice writeup mark! steve

CJM
01-20-2011, 08:38 AM
thanks steve

honda400ex2003
01-20-2011, 08:48 AM
your typing skills have def improved over the past few months! you should take up typing as a profession. lol steve;)

CJM
01-20-2011, 09:13 AM
So your saying I should be a secretary...

honda400ex2003
01-20-2011, 09:16 AM
LOL at least is a low risk job. lol could work for people taking notes also. lol steve