I put WB cams and a CDI BOX and a spring kit. I put it with the riginal pipe. I didn´t adjust the carburator and went to ride. I rode really hard for about 5 hrs. After I noticed that my valve had bent.

Does anybody know why?

I allready adjust the carburator and fix the valve and put the racing pipe in it, just hope it won´y happen again.

What could had hapened?

 

Well the obvious answer would be piston to valve clearance. When you took the head off did you re-use the original head gasket or replace it with a new one??

That can make the difference. All it takes is .010" to start smacking valves.

Also, did you happen to notice if there were any warnings regarding the cam you bought and the type of piston to use with it?

Some high lift cams need certain piston combos. Many pistons have near the same compression ratio yet the distance between the center pin and the top of the piston are different.

Are you using the stock rod or is it a stroker?

Do you know if the valve springs you replaced were stronger or weaker (my guess is they should be stronger) this prevents the valves to "float" at high rpm. By floating, I mean the engine is pushing so many rpm's the valves don't have enough tension in their springs to keep them seated to the camshaft, thus they tend to float.

This also could have caused your problem.

 

If I remember correctly early mojaves had weak valve stems.

 

The ones who repared my quad they lower the descompression of the motor, I am not really sure if this is how it is said, but what I know doing this makes the kick starter to be a little more hard. hope you know what I am talking about.

 

If it is harder to start then they raised the compression. It is more than likley a 11.5:1 ratio piston. They might of had the vavles adjusted to far out. I have WB cams, KLR250 black box, ported polished, stock vavle springs, Cobra JET pipe, and lots more on my 1990, and I haven't had any trouble with the motor. I would check the vavle clearence regularly.

 

Your trashed Mojave wouldnt have a good tail light youd like to sell would it?

 

JD are you going to save the trashed quad or are you interested in selling some parts as the previous post had questioned

 

Sorry I don't have any tail lights. I don't run factory lights. I plan on rebuilding it as soon as I find a good frame.

 

I went like in an 5 hr ride in my mojave on saturday. Power was great and all, maybe at the end it los a little power. Well today I tured it on and it had a sound in the head, like metal touching with something.

What could it be?