So recently my friend picked up a deal on a yamah warrior 98. Problem is, it doesn't run perfect. I'll try and give as much detail as possible.

The starter doesn't work so the pull start has to be used. But anyway, the quad idles decent, but if you punch the throttle, it dies out quickly. If you ease into it it will rev better, although sometimes it randomly DOESN'T die when you punch it, other times it does.

After an extended period of idling, it will just shut off.
It seems to skip beats and misses when revved higher, its just not smooth sounding.
Smoke appears a little whitish gray when revved high.
Sometimes it takes a little longer to get pull started, other times it starts right up.
Sometimes drift starting will not even work.
Often, idling would go up really high, finger the throttle and it would go back down, and view versa.

Yesterday I found that the accelerator pump inside the carb seemed to be getting stuck, so I replaced the acc pump spring with a stronger pen spring. I didn't get to test it much today, but that it may have fixed some problems with idling high and starting problems, or who knows maybe it hasn't.

So yea.. mainly the problem seems to be that its just not running smoothly at all. You really have to take it easy on the throttle or it will quickly die. Im thinking it might be the air/fuel mixture but the more I research the problem the more other problems I find out it could be. So I just thought id post exactly what's going on with it in here.

Oh it might help to know that the previous owner said it has been bored out with a wiseco piston, and it has a KN air filter. I checked the garb and jets for debri, nothin in there as far as I can see.

Any help would be greatly appreciated.

 

First thing you need to do is get a compression reading.
If that is good then you can go on to other things.

Also sounds like you have a vacuume leak to me. You need to check the boot and other things and look for a vacuume leak.

 

Hmm alright thanks. I think I've found some issues though. After reading up a lot on the problem it seems the parking brake sensors on warriors are known to go bad and cause a sort of rev limiter to kick in. I unhooked the parking brake sensor and it seemed to fix the problem and allow me to rev high and punch the throttle as fast as I wanted. However after just a few minutes of riding it still seems to act up.

Its still dying down when I hit the gas during idle now, and sometimes when it DOES decide to run, it will also cut out at about 3/4 RPMs. I had been thinking it was the carburetor, but after messing with the parking brake electrical cables I'm beginning to think it's an electrical issue. Does perhaps the reverse switch cause problems if the sensor/wiring in it go bad as well?

Can anyone else help me with the issue?