93 RM125 wont idle

Hello all, long time reader, first time poster. Love the site!

Just got a 93 RM 125. Bike supposedly had a somewhat fresh complete rebuild not too long ago (PO gave me receipts).

It didn't idle at all, even adjusting the air screw. I looked at the jets and it had a 340 main and 40 pilot. So I went down to local powersports place and went back to stock jets, a 360 and 55.

after I put them in today, it started right up and idled. Took it for a ride, ran great, but didn't idle.

I'm new to the Mikuni TM series carb. I notice there is the idle screw in the lower right corner close to air inlet, and another screw with a lock nut on it in the upper middle area.

not sure what the one with the nut on it does, but if i screw it all the way in it locks the throttle in place.

Suggestions?

Steve

the locknut screw is your idle speed screw, and the one down by the airboot is the air screw. dont hold your breath on the mikuni tm's i've never had a 125 with a tm idle worth a damn.

the locknut screw is your idle speed screw, and the one down by the airboot is the air screw. dont hold your breath on the mikuni tm's i've never had a 125 with a tm idle worth a damn.

Thanks for the reply! On the screw with the nut, will screwing it out increase or decrease the idle? Any suggestions on where to start as far as how many turns out on both screws? I'm thinking 1.5?

well the bolt has a finger poking through the carb and pushing the slide up, tightening it will raise the slide (idle) and backing it out will lower, 2 out is usually where i start. but remember your airscrew needs to be adjusted with your idle, out for more air and in for less

well the bolt has a finger poking through the carb and pushing the slide up, tightening it will raise the slide (idle) and backing it out will lower, 2 out is usually where i start. but remember your airscrew needs to be adjusted with your idle, out for more air and in for less

I'll mess with it some more tonight after work, but i tried adjusting that and didn't see any change either way. Weird.

well. like i said, they're a pain to get to idle. might want to check your pilot circuit, make sure it's clean. make sure your air filter is clean and oiled, make sure your reeds arent crap and for shits and giggles check your compression

well. like i said, they're a pain to get to idle. might want to check your pilot circuit, make sure it's clean. make sure your air filter is clean and oiled, make sure your reeds arent crap and for shits and giggles check your compression

Thanks for the suggestions, will check tonight. Thing runs good everywhere else! Guess i'd rather it not idle and run good up top :)

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