I have a 90cc baja ATV that seems like the rev limiter is kicking in. The unit is about 5 yrs old but had been ridden very little. When I first purchased it I could adjust the small red screw on what I assumed was the rev limiter located under the left rear fender against the frame. This would change the rpm at which the limiter would kick in. If I unpluged it I had no limits to the rpm. Well now no matter where I set the screw or if its plugged up or not it kicks in at a fast idle. It won't even run fast enough to ride. Is this actually a rev limiter issue or what? Any advise would be greatly appreciated. My daughter is tired of watching her 4wheeler collect dust because Dad doesnt know what to do with it.

Im am assuming it is some type of limiter because when you push the throttle is starts missing but the miss is perfectly consistant and once it starts it maintains a steady RPM no matter how far you push the throttle. Its not irratic at all like a normal misfire would be.

 

You said that if you unplugged the rev limiter before that the engine speed used to be unlimited. That makes complete sense to me. If you remove the thing that limits engine speed, then the engine speed will be unlimited.

But now you say the rev limiter is still kicking even when it is unplugged. How can that be? Think about it...

More likely you have a dirty carburetor. The idle circuit is fine, yet the pilot jet is plugged. That would limit you from accelerating much above idle. This is a classic symptom on quads that have sat a while with stale gas, or quads that don't have fuel filters.

Read the "sticky" on carburetor cleaning, and be sure to search you tube for helpful videos. Even if your carburetor is not exactly the same the principles are still the same.

 

Well duuuuhhhh. Good point. I was thinking it was something other than the rev limiter causing it but i guess there is nothing else electronic other than the limiter that would cause it so if its unplugged and I still have the problem then the problem must be elsewhere. Should I invest in a carb rebuild kit or just disassemble, clean, and reassemble?