iv got a 1985 rm 125 and a couple weeks ago I was riding and all the sudden I was about to hit the power and and it just sputtered. I replaced the plug and it helped but didn't resolve it. I pulled the top end and everything's in good shape. I'm just waiting on gaskets and I'm replacing the reeds even though they don't look wore out. What do you think it could be??
1985 rm 125 high rev sputter issue
- Thread starter BigButter
- Start date
Most people don't realize what the life of a float is like. From day one of the engine running, the float wears and the little tab is subject to bend allowing the float bowl level to rise. That makes for a rich mixture that suddenly misses on top as too rich. It's cheap and easy to rectify. You can usually save anyone willing to help you some time if you describe in detail what your used sparkplugs look like when you remove them.
that one is really the easiest one to set of all of them that I have worked on. I do believe that the stock mikuni had two individual floats that move independent of eachother. I really like that design in concept. First thing is to make sure those two different floats act similarly and are not partially full of gas. do that by shaking them next to your ear and putting them in a pan of water and observe how they float.
the arms that those ride against have to be parallel with eachother and parallel with the cab mating surface when resting on the float needle and the carb turned upside down. it's an easy one. after that make sure that the float needle actually shuts off the fuel. needles and seats are easily replaced and fairly cheap for the mikunis.
