I have an '84 rm 80 that won't rev. The air box has had the air filter supports cut out of it. I covered the hole with two layers of low density home a/c filter foam and held it in place with the bolt on support ring. The bike had a new piston and rings, and starts very easily. The throttle can be held below half throttle and it will eventually rev into the powerband. If it is twisted open it just stutters and stumbles. The clip on the needle was in the middle position. I moved it down it got worse. I moved it up it got better. It is now in the top position. I'm afraid it is sucking too much air. The carb is a mikuni I believe it is stock. It has no adjustments other than the idle. The local shop confirmed that it had no exterior adjustments. Is this true? Do I need to re-jet? It seems so, but I am unsure of how it all relates. If it is pulling more air it also needs more fuel right? Is the pilot what needs changed? Someone shed some light in my direction!
thanks