jetting HELP

[kevinmfaust]

I just purchased an 03 RM 250 with about 20-30 hours.....very nice bike. The dude that I got the bike from was riding at about 4000 ft elevation and I am at 500 to 1000 ft. I have been moving the jetting around and the top end is good but the low end is not crisp and it stalls some time just off idle. Currently I have a 165 main jet, 38 pilot jet, needle in the 2nd clip and air screw out 2 turns. I have been using Canadian Daves artical on how to jet. Today I changed the piolt from 40 to 38. It cleaned it up but I still have the stall but not as bad. When I do the idle test it tells me to go smaller still on the pilot. My problem is just off idle. From everything I have read I an jetted lean now. New plug, pipe is clear, clean filter, what up? Could it be the tps? The dude that I got the bike from said that the cylinder was ported for low end. Could he have screwed up the cylinder. He said he went with Gorr's specifications. Kevin :ahhh:

 

[elf]

If your problem is at 1/4 throttle you might need a leaner slide cutaway, Do a search for 03 rm 250 jetting. I think some of the guys were using a leaner slide in that bike.

 

[jp2396]

Look at a 45 or even a 48 pilot. That 38 and 40 seem a bit lean to be running down at your altitude. I had to drop to a 45 pilot from a 50 here at 4,700' ASL.