lighter flywheel?

[poopjz]

hello fellow kdxers
i have been searching for some time for a lighter flywheel for my 2000 KDX 200. i have made several modifications to acheive quicker revving motocross like power (pc pipe, eric gorr porting, boyessen power reeds) i am looking to use my kdx at the mx track. the flywheel effect dampens my acceleration and adds A LOTof vibration at high rpms. i ride on an abandoned farm on long island (good traction, high speed, some deep sand) with bigger mx bikes (CR 500, 520SX) i need all the help i can get. Is their a company that makes a lighter flywheel for my purpose? possibly a lighter weight with the ability to add on more weight? thanks for the help

 

[spanky250]

No amount of flywheel lightening is going to help you keep up with a KX 500 or a KTM 520 in any condition that allows them to get into the meat of the power. That said, the KDX engine is based on an older KX 125 design, so it may be possible to fit a KX 125 flywheel from this older generation, although I don't know what year 125 engine you would need the part from. You will lose the lights in this process, and you will also give up some of the lugability and tractibility that makes the KDX so friendly.

 

[Kawierider]

kx125 flywheel?

spanky250....
you said his 2000 kdx was based on and oldermodel kx125. Was the kdx based on a 125 earlier in its lifetime around say 1985? im looking for a flywheel (one of the magnets fell off of mine) for my bike and maybe this could be and alternative to spending 500 dollars on the stock one. thanks in advance
tim

 

[Canadian Dave]

Poojz you’d be better off changing your gearing to either the stock 47 tooth rear sprocket and a 12 tooth from stock or the stock 13 tooth front sprocket, 50 tooth rear sprocket and a 110 link chain. You can also achieve more MX like response from a simple jetting change. The stock B taper needle produces a nice strong/torque pull through mid throttle setting with a very controllable hit. Going to a C taper will cost you some of that grunt in trade for better, more immediate throttle response. There has been plenty of discussion on this subject over the past month on this forum, take advantage of others hard work.

I’ve tried a number of combinations in the past and more recently Acutemp (Dan) has been putting in some considerable time. A CEK jet needle in the #3 (mid) clip position with a 45 pilot, the stock #5 slide and a 152/155 main jet should be close, it worked well for both of us. Dan also reports good results with a CCJ in the in the #1 clip position (top) a 45 pilot and a 152/155 main. Before spending your hard earned money adapting a lighter flywheel I’d pick up a couple needles from Sudco at $5 each and play a little. Be sure to do a plug reading at WOT to insure you aren’t running lean on the main jet any time you are fine tuning your jetting. You can find instructions on the JustKDX home page. Follow the link below.

I’d think with the proper jetting and more aggressive gearing you’ll want to leave th3e flywheel weight alone or perhaps add some more. While your buddies are searching for traction you’ll be putting power to the ground.

Let us know how it worked out.

Kawierider give Fredette Racing Products a call. Jeff should be able to repair your flywheel or direct you to someone who can. It will certainly be much cheaper than a new one. Tell'm the guys from JustKDX sent ya.

David