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Rm 125 help plz

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hi i have a 91 rm 125. to start it i have to give it throttle idk why :smirk:. the problem is it wont idle it runs like half throttle the hole time. shit ton of smoke coming out of the exhaust. and black oil just spewing out the exhaust. i tore it apart and put new gaskets on it thought it might be leaking air its not. it has a hot rod crack and new piston. i did a compression test and it hits 150psi :bonk: what do you think my problem is? plz help.

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first check your oil mixture ratio. then you should clean your carb, sounds like its clogged or the float is bent. when you first get the carb off the bike shake it up and down. if you cant hear the float hit the bottom of the bowl then your float is bent.

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oil ratios fine. i tore apart the carb and on the carb there is a part that has a philpes end on the bolt. and a 8mm nut. that the slider hits on the left side. could this be the problem i have two carbs and was caomparing them and i think this is my problem? what does this part do ?

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the philips end is the main jet. and the bolt is the pilot jet. im not sure about what u mean when u say "slider". do you mean the carb slide. or are u talking about something else?

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no its not the jets. the 8mm nut is on the bolt that has a phillpes end.its on the outside of the carb. as slider i mean the throttle slider the piece that hold the needle :banana: . i clean everything and played with it and know it runs at half throttle till it warms up then goes to full throttle without me doing anything :bonk: idk wat is happen everthing seems to be working properly. :smirk: wat do u think it is?

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oil ratios fine. i tore apart the carb and on the carb there is a part that has a philpes end on the bolt. and a 8mm nut. that the slider hits on the left side. could this be the problem i have two carbs and was caomparing them and i think this is my problem? what does this part do ?

That nut on the phillips screw on the side is the idle speed adjustment. loosen the nut to turn the screw. turn the screw ccw to allow the slide to close more and that should lower idle speed. if the carb is gummed or jetted wrong this adjustment may not help until the carb is cleaned and jetted.

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alright would the pilot jet being to small make it run wide open?

If the pilot is clogged, causing a lean condition the bike will rev high upon starting. compression seems a tad low at 150 but is still runable.

if you dont have a service manual pick one up so you can figure out the names of all the parts you are dealing with. and that will give you stock jetting, which will give you a good starting point for your bike, but the first thing you need to do is verify your carb is squeaky clean

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its not im sure. and i did its clean as i could get it. and could the crank seals being bad make it run like this? i heard they could.

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its not im sure. and i did its clean as i could get it. and could the crank seals being bad make it run like this? i heard they could.

yeah, just take some carb cleaner and spray it around the magneto cover and see if the idle changes, if it does you need to replace your crank seals

It doesnt have to be carb cleaner, it just needs to be an aerosol and flamable

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so i was messing with the bike today and took the magneto cover off and put it on choke and it fire up and didnt rev. but when i took it off choke it started to rev like it was. what is this telling me?

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so i was messing with the bike today and took the magneto cover off and put it on choke and it fire up and didnt rev. but when i took it off choke it started to rev like it was. what is this telling me?

the choke is an enrichment circuit which means it adds fuel.. so that means you pilot jet is lean, OR your idle is set wrong, try turning the mix screw IN(clockwise) about 1/2 a turn or raising the pilot size by 1

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