Guys (or gals),
I need a little help here. I have an old bike that I have, but I am having a little trouble getting it to perform at its peak. The bike is a 1986 CR125R , the carb is clean and I have checked everything that I can think of. It starts great and seems to run strong most of the time. The one thing that I can't get ironed out is that if you go from an idle to full throttle as fast as you can twist it, the engine just boggs out until you let off the gas a little and then it takes off. If you apply the throttle slower it doesn't happen and runs fine at full throttle. Just seems to be with that quick twist that is the problem. I have checked the jets, the air cleaner, etc, etc. and can't find anything wrong. Need to check that old ATC valve yet. Any thoughts or suggestions would be greatly appreciated.