Rm125 can't rev into powerband?

[Atrufant73]

I have an 01 rm125 that sounds like its hitting a rev limiter before it has a chance to hit powerband. I cleaned the carb, it has a 460 main and a 30 pilot jet but i do not know what the clip on the needle is since i cant get the throttle cable off the slide, the plug has almost no oil and is a golden/darkish brown which to me looks good, replaced the top end, flipped my reeds, my powervalve is free but it doesnt open all the way cause I cant get it to rev high enough I am pretty sure, and I sprayed carb cleaner in my pipe and put nuts and bolts in it and shook it around for 10-15 minutes but still no change. Starting to think its something electrical but for now I'm lost, HELP!

[Mikel.Laundry]

so its not reving out. air filter clean? show a picture of your spark plug you could be to lean

[alpinestars799]

no power but revs out real good?

sounds like lean fuel mixture to me

[Atrufant73]

Oiled airfilter after i rebuild top end havent even riden it for more than 45 minutes. The sparkplug is a br9eg.

[Atrufant73]

This video FYI I know the air filter is off I thought it was running rich but taking the filter off didnt make a difference

And this video is of my powervalve linkage, I'm guessing its ok its just not revving high enough to open all the way but it does seem to vibrate a lot!

[maxamillion125]

Your PV is not opening. Remove right side cover and see if the power valve is sticking. Try turning it by hand.

[Mx Factory USA]

It start doing this before or after the top end rebuild? You check the compression after? Seems like a faulty TPS or CDI

[Wild Alaskan]

clean all the electrical connectors, had something similar happen to one of my bikes

[Atrufant73]

Maxamillion125 my pv does open on its own somewhat if you watch the video and it moves freely by hand, I just think it can't let itself rev high enough to let the pv open all the way but I'm not 100% sure

MXpro787 Before the rebuild it could rev a lot higher but made similar spitting and sputtering noises just when it started to get on the pipe and it had no power, the rebuild kinda made it worse haha I don't have a compression tester but just kicking it over the difference is night and day.

Wild Alaskan I will surely try that later today when I get the chance.

[Atrufant73]

Heres a better video of the powervalve, I'm pretty sure its the culprit. It seems like the exhaust gases is the only force opening the valve by the looks of it but I'm still not too sure.

[jamesmusic19]

That sounds like a rich condition to me. Just because taking the air filter off didn't help it doesn't mean it's not rich still. I would try raising the clip on the needle a position or two and if that doesn't help then try going down a size on your main.

[Atrufant73]

That sounds like a rich condition to me. Just because taking the air filter off didn't help it doesn't mean it's not rich still. I would try raising the clip on the needle a position or two and if that doesn't help then try going down a size on your main.

Look at the pics i posted of my plug its not wet and its brown which to me looks about right

[drmcook]

I'd say it's too rich too. 2001 Came rich from factory and it came with 27.5 pilot. When I had an 01, i went down to 25 and 450 main for the summer, and it made a big difference. Can't really judge the jetting by the color of your plug unless you do a proper plug chop test. Also, this is not the right pug for your bike. Get the OEM plug. It's $30 and it will last a while.

[Atrufant73]

I'd say it's too rich too. 2001 Came rich from factory and it came with 27.5 pilot. When I had an 01, i went down to 25 and 450 main for the summer, and it made a big difference. Can't really judge the jetting by the color of your plug unless you do a proper plug chop test. Also, this is not the right pug for your bike. Get the OEM plug. It's $30 and it will last a while.

I did do a spark check the right way, I dont understand how it can run so rich that it cuts off before powerband and wont foul a plug anyways. I'll think about getting one of those fancy plugs after I get it running correctly. The powervalve linkage does not look out of the ordinary to anyone?

Edited May 15, 2013 by Atrufant73

[drmcook]

Did you try adjusting the power valve spring?

[Mx Factory USA]

Tps is used to trigger different ignition maps programmed in the CDI. If its not picking up the right ignition map it will run in limp mode so to speak. Bypass/replace the TPS I'm sure that's your issue

[rob the snail]

i have an 86 yz125 thats doing the same thing...when i race it (vintage bike) it revs on the stand but when in gear on the track it feels like its not going into high revs....pulled the pv cover off and it seems to be moving, about the same as that video showed

the top end looks very new as t previous owner said he rebuilt it ans looks like it has no work on it at all, the whole bike has been restored and is in mint cond except for this problem, i did a compression test and was only getting 80psi. i had throttle open fully and pressed kickstarter about 8 times..think thats right but there is no way the top end is that bad

HELP PLEASE

[Mx Factory USA]

i have an 86 yz125 thats doing the same thing...when i race it (vintage bike) it revs on the stand but when in gear on the track it feels like its not going into high revs....pulled the pv cover off and it seems to be moving, about the same as that video showed

the top end looks very new as t previous owner said he rebuilt it ans looks like it has no work on it at all, the whole bike has been restored and is in mint cond except for this problem, i did a compression test and was only getting 80psi. i had throttle open fully and pressed kickstarter about 8 times..think thats right but there is no way the top end is that bad

HELP PLEASE

Dude your compression is too low it should be double that. I'm surprised it even starts

[Atrufant73]

Did you try adjusting the power valve spring?

No is that the circe shaped cover on the left side of the jug?

Tps is used to trigger different ignition maps programmed in the CDI. If its not picking up the right ignition map it will run in limp mode so to speak. Bypass/replace the TPS I'm sure that's your issue

I am 99.99% sure a TPS does not exist on my bike, I just looked through the electrical portion of my manual and didn't mention anything about one.

[Atrufant73]

i have an 86 yz125 thats doing the same thing...when i race it (vintage bike) it revs on the stand but when in gear on the track it feels like its not going into high revs....pulled the pv cover off and it seems to be moving, about the same as that video showed

the top end looks very new as t previous owner said he rebuilt it ans looks like it has no work on it at all, the whole bike has been restored and is in mint cond except for this problem, i did a compression test and was only getting 80psi. i had throttle open fully and pressed kickstarter about 8 times..think thats right but there is no way the top end is that bad

HELP PLEASE

Check your reeds compression could be leaking out of your reeds if they are severilary damaged. BTW this is the gap my reeds have, does anyone think this is causing all my issues?