watch this video and help me out!

my rm 125 idled ok till today when i fired it up and it wont idle at all even with the idle screw completely screwed in,my plug is wet with oil so i changed it and it did the same thinking i need a leaner pilot jet because its really boggy when i rev it starting to get pissed of with this bike,please try and help me.I did a compression test and held the throttle open and kept kickin it till the needle on the compression gage stoped.the bike has 20 hours on a fresh top end.

First off, i would say get a manual for your bike, they're great. You never did say how much compression the engine has. What oil ratio do you run? And how do you ride your bike (Woods, Track, etc)? You probably should pull the carb and take it apart to check everything out, see what jets you have, and to get it cleaned up. Report back with jet sizes and other answers

Edited by aaronjohn20

i have the manual,the engine has 150 psi,i run 40:1 amsoil dominator,i ride my bike on logging roads and woods and trails,took the carb apart like 10 times this month and a half and checked it out and dissasenbled and cleaned it,could my float hight be off?stock is 175,55 and im running 168,50 because i am running an fmf pipe and that is what it recomends and two turns out on the air/fuel mix screw.hopefully this is what you were looking for

What position is your needle at? Is your plug black looking? How do your reeds look? Whens the last time your crank seals were changed out? Warm your bike up by riding it around, then have someone hold you throttle open just a lil so you have a steady engine speed and move your air/fuel screw in or out in 1/8 inch turn incriments until your bike idles the highest. Do not adjust anymore further than that or you'll have a flat spot. Let me know how many turns your out after you do that. You may try and lean out the pilot some more but i would prob wait for some others around here to start chimeing in.

This happened to me. Either you have way to much oil in your gas, possibly you made a mistake measuring it (it happens), or your needle is in the wrong slot

I would pull the carb and start over. First I would reset the float height and then I would make sure the jets were tight. Ever had a jet fall out? Next I would see if the slide needle c-clip broke. Run the c-clip on the 2nd or 3rd groove, if its on the 1st, 4th or lower on the needle, then you need to re-think your jetting.

Getting your jetting right can be a headache but once you have it all worked out you'll be glad you took the time.

Hang in there, i'm sure the guys will all help you get it worked out.

ok,thanks for your input guys,im gonna tear the carb apart again and check things out,the needle is in forth position so i should i think im gonna try the fifth position and ajust my float hieght and see how that works plug was soaked black,the last time i looked at my reeds they were fine but i got some boyesen reeds on the way,i turned the air screw out to 2.5 and still didnt do anything,i will ajust my idle with what you have recomended and let you mix ratio is 40:1 and i put 250ml of amsoil per 10 liters of fuel.

lol,5 is lower,nvm,im gonna set the neeedle position to 3

Double check the pilot jet. May be dirty or blocked. That circuit controls the idle. If it just started doing it, it is probably something in the carb blocking a jet. And as Padgett said, check float height and make sure shut off valve on float is working.

ok will do,im gonna start workin her right now.i will let you know how things turn out

What have you figured out so far?

well,i have dissasembled the carb and cleaned it,i bound that the float looks kinda crooked looking,here are the pics of it.




Refer to your manual in the following sections: Chapter 8-Fuel System, and then Float adjustment. Measure your float height before you change anything and make sure it's within factory spec. Oh Hell, your float height is supposed to be 16.0mm or 0.63 inches. I'm not sure if you mentioned before or not but what is your altitude? Let me know what you come up with

im pretty sure im at sea level almost,give or take 50 feet,and yes i read the manual about the 16 mm float height,but i have co caliper to measure the hight with at the moment,so i figured for now i would make the float even and not look un even and see how that works,plus i think the float was stiking every once in a while because of going to pick up a verniere caliper and measure it tomorow.thanks for helping me out so far

I used a 5/8 open end wrench to check my float height because 5/8 of an inch is .625 inches which is real close to the .63 stock float height. You need to read and do what your manual tells you in the float adjustment section. Also hold your carb around a 45 degree angle to keep your float from depressing the spring loaded pin in the float valve. You want your floats touching the pin, but not depressing it.

ok,thanks man,im gonna try that with the 5/8 wrench,i bent the float side that was un even and it idles pretty good now,but i am going to check the proper hight tomorow with what you have suggested.

yeah your bent float was making your carb's bowl not fill up all the way, thus not having enough fuel. Hopefully thats the only problem you have. Let us know, and glad to help

Are you adjusting the floats by bending the float? Or are you bending the tab that presses on the float needle? Should be bending the tab, floats should always be level with each other and the tab adjusts the float height.

Padgett-If you look at one of his photos you can tell that one of the floats was cock-eyed.

rm125dude-You should prob just get a new float. I'm sure that they can't cost a whole lot

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