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2003 rm125 powervalve adjustment?


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i have a 2003 rm125 that i just got and first time i went riding i noticed the bike wasn't hitting power band at all! First i thought it was the clutch slipping so i called the guy i bought it from and he said he changed both clutch and basket but he did tell me that when he rebuild top and bottom he didn't really adjust the power valve right and told me to check that before anything else. I wanted to know if anyone can tell me where the adjustment bolt is located and what i need to do.

is this where i can adjust iT?????????

Thanks

Edited by maks630
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Wish I knew how to help adjust, but I can't figure it out from looking at microfiche. You could take the lright side cover for the power valve and see if it moves freely and if the guy actually rebuilt the top end. If he didn't, it would be all gummy in there. Maybe someone else can chime in on how it's adjusted. Some bikes have a cover on the left side that turns to tighten and loosen the spring for the power valve, but I'm not seeing that on yours.

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The cover above the exhaust pipe , is really hard to get off , with the frame rails, going down right in front.........I put my cylinder on ....then tried to put on the cover....no bueno'...learned that lesson.

You can , do what the above guy said....and take off the right side p/v cover...disconnect the plastic clip. from the rod....and then try and move the p/v...and get some idea , of your problem......should move freely.

Some say you can adjust the p/v .....I don't have the manual.....so can't really say....but I don't have any issue with my 05 rm 125....except a leaky carb bowl.

Runs like a top.

good luck.

xxx

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If it's the same as the 03 250, which I'm pretty sure it is, it's on the top left on the cylinder. it's a little hand screw about the size of a silver dollar that has a 8mm head bolt on either side. Loosen off the bolts, let spring return to position, then turn 180 degrees clockwise and tighten off 8mm bolts to hold.

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The right side is to access the rod .....which goes from the p/v to the crank.

You take off the rod.....to pull the cylinder...

The left side is where the adjusment cover is.....not sure what to do here....as I don't mess with mine.

But it has 2 8mm nuts to take off and then the slotted ( dime size cover) is either the adjuster or the cover to take off to gain access to the adjuster.

Nice pipe.

Good luck.

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i just took a look under them hoses and there are no covers, no bolts, no adjusters. Should i check if its sticking? if so would i need to take off the right side cover or the front cover where the pipe comes out?

heres a better pic of the left side

http://s1219.photobucket.com/albums/dd433/maks630/?action=view&current=IMG00071-20110529-1349.jpg

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Remove right side cover and see if the power valve is sticking. Try turning it by hand. You may have to adjust it from the front of the motor under the cover above the exhaust. But you may need to pull motor to do that. Unless you disconnect the carb and radiator hoses, spark plug, then bolts and brackets to frame but not swing arm and maybe you could tilt it back far enough to get at the cover. If not, then only swing arm to pull to get it out. Check movement on right side first. Maybe push rod is not connected or something that simple.

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  • 9 years later...

Adjust power valve 1/2 turn Anti-clockwise and see how that goes... loosen to the 2 little screw and with a pare of pilers turn the valve :)   I just took abit of top end out of my 125 for more bottom and mid... heaps better to ride :)  CLOCKWISE for bottom-end ANTICLOCKWISE for top end. easiest thing to do on a 2 stroke. Mine is a 2000 mdl so I don't know f the 03's are different. Just realised this post is 10 years old haha/ but if any one new reads this, well it helped me out yesterday. bike is amazing for rocky hills and tech stuff now. wow

Edited by Justinian Leonidos
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On 10/2/2020 at 11:25 PM, Justinian Leonidos said:

Adjust power valve 1/2 turn Anti-clockwise and see how that goes... loosen to the 2 little screw and with a pare of pilers turn the valve ? I just took abit of top end out of my 125 for more bottom and mid... heaps better to ride ? CLOCKWISE for bottom-end ANTICLOCKWISE for top end. easiest thing to do on a 2 stroke. Mine is a 2000 mdl so I don't know f the 03's are different. Just realised this post is 10 years old haha/ but if any one new reads this, well it helped me out yesterday. bike is amazing for rocky hills and tech stuff now. wow

So just for clarity on my part..... my service manual says when reassembling to turn the exhaust valve cap clockwise one turn. So you took it a half turn back from there?

Thanks!

Edited by forty5cal1911
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