2002 kx 85 problems

[swamprat]

I have a low mileage kx 85 that is on its second crank in two months. Good gas,good oil.32:1. No air leaks and good clean filters.The last crank had a wiseco hotrods kit installed by a reputable shop.It lasted three rides and one race.Are there any defects or tips available to eliminate this problem. I am thinking there is some inherent problem with this crank and wonder if replacing it with a new Kawasaki unit will solve this problem. All input will be appreciated.

 

[Binky]

My kid has a 2002 KX85 that was ridden and raced all of 2002,Not a problem.
Same for about 15 other kids that ride KX85's at our local club/track.

I do know that our Kawi guru (Tom Zont) has told me that he prefers to
never rebuild the kaw (65 - 85) cranks when the rod needed to be replaced
because they never were quite right afterwards, He has convinced me
to just do a new crank/rod assembly when the time comes.
You could call him at Great Escape Kawasaki for more info...

 

[ktmdad]

Usually if the crank goes that quickly after being rebuilt it's due to improper reassembly.

Take Binky's advise and simply buy a new crank assy. It's less expensive, in most cases, in the long run.

 

[swamprat]

Thanks guy's. That is the way I am going with it. I ordered the new crank assembly today. After measuring every point I could think of I agree with the summation of improper crank assembly. What I can't figure out is why the first one went out. The counterweights on the expensive trot-line weight were not of uniform build and anything that needs to be this precise should measure the same. When I get the new one in I will measure and compare.

 

[ktmdad]

We had a lower connecting rod bearing go out on our RM85 due to the springs on the exhaust pipe falling off due to breakage during a really dusty race. Enough dust and crap was sucked into the motor from the exhaust port to ruin the bearings.