Jetting for my bike?

[JONO250]

not meaning to jack your thread dude, but I have a question for dajogejr

dajogejr,
I have a 96 Rm250. It is always fouling plugs. The bike never idles and revs high when it's cold. The bike feels zingy up in the top end but does not make any power up there. Around 1/3-1/2 throttle I get black smoke out of the exhaust.

Mods are:
wiseco piston
fmf pipe
reeds

What do I need to do jetting wise?

[dajogejr]

Originally Posted by JONO250

not meaning to jack your thread dude, but I have a question for dajogejr

dajogejr,
I have a 96 Rm250. It is always fouling plugs. The bike never idles and revs high when it's cold. The bike feels zingy up in the top end but does not make any power up there. Around 1/3-1/2 throttle I get black smoke out of the exhaust.

Mods are:
wiseco piston
fmf pipe
reeds

What do I need to do jetting wise?

Honestly, you might be beyond jetting help. Fouling plugs, no power up top and feeling zingy tell me a few things.

Worn out top end (lack of compression and fouling plugs) and zingy sounds like lean jetting up top and/or an air leak.

First thing I'd do is check compression. I honestly don't know what it is for an RM.
Then i'd do a leakdown test. You can buy a tester for a single cylinder pretty cheap. You plug the intake and exhaust, pump 6 PSI in there and hold it for 10 minutes. If it holds...or drops less than 1lb per minute, you're ok. If it leaks more/faster than that...you've got a bad seal, gasket...something.

In my experience with my CRs (one 94 and two 97's) the pipes from the factory are WORLDS better than the pipes on a banshee. You don't have to go as drastic on the jetting....

I would find out what spec stock is....get back to that...and maybe bump the main size a size to three. Also...have you done any powervalve maintenance?
A gummy/sticky powervalve can muck things up too....

[RMX250MB]

gotcha...thats what i thought. I have a few projects to do on it before i am ready to start it up again...but i will use your advise and hopefully i can figure it out. Thanks a bunch everybuddy. Now all i have to do is figure out the easiest way to put swing arm bearings and fork seals in.