RM250, low response, no revs, low power

[SoFlo]

I just traded my quad for a non running 1996 RM250.
We cleaned the carb, and set the float height. For some reason it was so outa wack it wasn't even letting gas into the bowl?
So we measured from the bottom tip part of the float, to the deck of the carb, right were gas starts coming out, to 16mm. The main jet is a 172. Forgot to check the pilot, probably stock, and the screw about 1.5 turns out. (37mm PJ)
The bike has an FMF pipe and silencer, and an airfilter, otherwise looks about stock.
Well we check the plug, it's a RC12YC, I do a search, find that it's for lawn equipment! :yikes: So I put in a BR8ES. The dealer reccomended a BRDEIX, and Suzuki calls for a R6918B-7, don't have either right now.
Either way, the bike starts right up, smoking preety considerably (I put in Motul synthetic at 40:1) and I let it warm up for a few minutes and take it for a test run.
Well, the bike won't rev past like 2/3's, unless you make it do it unwillingly. And it has no response while riding or idling, very slow and sluggish all around.
I'm sure there's a problem, but the jetting is right were I always hear suggestions, even if I fine tune it I don't think it'll fix something this bad.
I'm going to order the Clymer manual for it, and inspect the powervalve, change the tranny oil, check the reeds, I'm not sure what else to do.

 

[sick 96 250]

did you check the compression and see where its at? On my 96 rm250 I had my jetting at 168-170 main, 55 pilot, 3rd clip and 1.5 turns out on the air screw. You main doesnt sound rich enough to throw it out of wack but maybe it is. BR8ES will do fine for your plugs, I ran them in my 96 constantly and never fouled, my 99 doesnt seem to like em to much though. You seem to be on the right pace with ordering a manual and going from there. Good Luck :cool:

 

[Tom Dixon]

Check the pipes. The expansion chamber may be plugged right up from "dirty" burning oil or the silencer has a blockage some where. On my KTM the spark arestor was clogged up and wouldn't rev at all.

 

[darringer]

Either way, the bike starts right up, smoking preety considerably (I put in Motul synthetic at 40:1) and I let it warm up for a few minutes and take it for a test run.

Could possibly be a right-side crank seal leak drawing tranny oil into the bottom end. The bike will smoke quite a bit from burning tranny oil, and your throttle response will be terrible. Change the tranny oil, run the bike for awhile, and re-check the level. If it's low, there's a problem with the seal.

 

[SoFlo]

Alright, the manual should be here early this week. So I'll check the exaust, and valve, reeds, tranny oil. I hope I don't get too many problems, but as long as I get it running well. :ahhh:
Oh, is there any problem with using a cheapier compression tester, like a $50 one?
And how about doing a leakdown test?

 

[SoFlo]

Also, the bike is very quiet, sounds like the engine itself it louder than the exaust. It seems to have more response when cold, as it warms up the response goes down some.

 

[snb73]

If you haven't done so already, clean your air filter. Don't lube with motor oil, use a good quality foam air filter oil.

I agree with checking the pipe/silencer. Take the pipe off and check for obstructions. Repack the silencer, new packing is around $5. While the pipe is off, check the "power valve" is functioning properly.

I always keep a plug in my silencer when I store the bikes. But I did find a mouse had made a very comfy nest in my air box last winter.

Good luck, Steve.

 

[rodH]

sounds a LOT like problems I was having

Links:

http://www.dirtrider.net/forums3/showthread.php?t=120399&highlight=valve

http://www.dirtrider.net/forums3/showthread.php?t=120448&highlight=valve

http://www.dirtrider.net/forums3/showthread.php?t=120512&page=2&pp=10

It HAS to be something that someone listed for me. Check the pipe flow 1st (it is the easiest too).

Good luck

 

[rodH]

Also, the bike is very quiet, sounds like the engine itself it louder than the exaust. It seems to have more response when cold, as it warms up the response goes down some.

This really makes me think it is:

1st-Clogged silencer or Pipe
or 2nd-non-functioning exhaust valve

Once you get this running right, you will be sooo stoked, I was seriously ready to by a new bike, now I am soooooooo happy!!!!