Rm 250 rev limit issues

So I took my rm250 out for a ride over the weekend and she went good for its of the day then I went I climb up a fire break and I noticed that it had lost all is power would just both down to nothin. So I went out in to a flat paddock for a burn to try work out wat was going on and I would get to about quater throttle and it wouldn't jump in life in the power band area instead just rev limit like no tomorrow any ideas anyone

Edited by BarnettN

Where are you from? I am from Canada and I had to raise the needle in the carb because of this issue.

I should explain. It is cold here now, so the air is thicker. Meaning more air, same amount of gas. I will drop the needle back down at the end of next spring.

New Zealand and where just comming in to summer me a and a mate pulled her apart and look at the reeds, power valve, changed plug and shortened the lead just case it was cracked, new fuel, pull the carby apart and cleaned her,new air filter pulled the fly wheel cover off for a look. Every thing seem good she starts and ldels like a dream but as soon as its under load no ones home as far as power goes

Does it smoke at all? White smoke means that its to lean and you should raise the needle and dark smoke means to rich and you should drop the needle. What colour was the spark plug?

Nar she smokes f##k all ae run it on 40:1 with 96 the plug look good wasn't super oily or anything ae the one that was in there wasn't the old but we put a brandy newy in just in case but still no better

Do a compression check. 150 psi is pretty close to a new motor and you should change your top end at about 120psi. I had low compression on my old bike and it would do nothing if I went past half throttle.

My mate that looked at it with me used to be a bike mechanic and he reackoned that it still felt pretty good ae as far as kicking it over went

What year is the bike?


You said you took the powervalve apart. Just yesterday I decided to play with my adjustment a bit. There is a preload adjustment that will give you more top or bottom end power. Is it possible that that came loose and all you have is bottom end?

Yea that could be possible didn't check or try it coz u had a couple of crack at getting up the fire break and even though it was bogging down and not that 2 stroke rev it balls off power I'm use to it did keep going and climbing till I reared it over it was very torquey and tractor like

If I have this right, turn the adjustment counterclockwise for more top end. Not too much because on mine it moved it so high that I couldn't, hit it without having a blown motor scare. Start with 1 turn tops. If that doesn't work change it back and try a hotter plug. Ie if you are running br9's move to br8's. because my bike won't hit the power and unless its hot.

I really don't want to say its electrical because in modern bike fixing electronics is fairly expensive.

Not to discredit ya plug idea but it's always had more than enough grunt for wat I'm doing up until just now with the plug s in it. But I'll deffently have a play with that adjuster.

That adjuster makes a huge difference. If you turn it counterclockwise it will sound pingy on startup with more top end and if you turn it clockwise it will sound real smooth on startup with more bottom end. I typically stop turning clockwise when the spring will turn the adjuster on its own. It's a real easy adjustment that I change everytime I got from pit to woods or vise versa.

this is a link to the video that I used. My bike however does not click like the on in the video, it is more of a fine adjustment. Good luck.

I hope that's wat it is some people I've talked to reckon it could be a electial fault like the stator or coil starting fail and casusing a brake down in spark under load any thorts on that side of things

Even worse it could be that thingy that I can't remember the name of behind your number plate. $$$

Hahaha I don't like the look of those dollar signs. But thanks for the help I'll try play with that adjustment tonight

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