kymike

Member
Nov 16, 2003
6
0
I have read about all of the modifications that can be made to increase and improve the KDX 220's power. But are there any negative effects from these mods? Does the added power put more stress on the engine that can cause failures? Will the stock piston and rod hold up in the long term to the added stress? I think the stock piston is a cast one. Would a forged piston be good insurance?

What about the clutch? The stock clutch is a little weak compared to other bikes intended for racing and more abuse.

I really like my 220 and just want to make sure it stays together once I turn it into a rev monster.

Mike
 

JCW

~SPONSOR~
Jan 23, 2003
333
0
Power and extended high revs obviously create stress on any engine. I would make sure you listen to the bike, use common sense, don't let it rev for a long period of time, clean the air filter often and change oil often. Maintenance, common sense, and proper jetting are the keys to enjoying your bike for a long time. Obviously, you already knew that- just a reminder.

JCW
 

Robcolo

Member
Jan 28, 2002
342
0
Originally posted by kymike
But are there any negative effects from these mods? Will the stock piston and rod hold up in the long term to the added stress?

What about the clutch? The stock clutch is a little weak compared to other bikes intended for racing and more abuse.

Mike
There are definately negative effects. If you ride tight, slippery, rocky, steep trails the stock engine is far more user friendly. I've "hopped" mine up and now like an MX engine it's practically unrideable in the really nasty stuff. [Sure is great in the desert though] So now I'm having to add a [$100] flywheel weight just to tame it back down a bit. You WILL have to replace the piston. Many threads on here have related to exploded 220 pistons - some even before altering the engine. Wiseco is about the only choice I know of. Cast pistons are just fine - it's the quality of the casting that's the problem with the KDX -lousy. The clutch will also slip with your new found power -and it makes a terrible noise. There are heavier weight springs available and past threads have listed those part numbers. You didn't mention suspension though. Once you get a KDX going over 30 mph the suspension is totally inadequate and it WILL hurt you. They understeer, they oversteer, and the front forks become terribly harsh. You'll need to revalve and respring the front end to get a comfortable and predictable ride. Stiffer front springs are an absolute must if you ever plan on going past 3rd gear.
 
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