Monday I bought a 87 250r. The guy that I bought it from said that he was running it rich. Today I finally got to ride it. It runs really good as long as you are reving it constantly. It has a 89 paul turner race exhaust and the cover off of the air cleaner. Do I have to rejet it to lean it out or do I have to mess with the air fuel mixture or what? I went through two plugs during the three hours that I was riding. I don't know very much about 2 strokes, but I think that is to many. Can anyone help me or is this just something that I have to live with.

 

I've never fouled a plug on my R's, 3 different motors! First, what plug are you running? NGKB8ES or 9ES is what I always run at .024" gap. What size carb do you have and what size main jet are you running? Is the cylinder a stock one or a big bore? You say it runs good as long as you constantly rev it, meaning it doesn't idle? Frankly none of my R's never did idle which is fine. More importantly it's how they run, screw the idle problem. Is the motor cutting out on the top end, if so that's an indication you may need to go to a smaller main jet but you need to give us more information. Do a plug chop test and read your plug. Get the quad out where you can really open it up, get it close to full throttle for a few seconds and then kill the motor at the same time you pull in the clutch. Coast to a stop and pull the plug out and see what it looks like. More info please!

 

I really don't know a whole lot about the bike yet. From what the guy told me He had the motor rebuilt 2 years ago but really hasn't riden it very much. From what I understood it is a stock motor. It has a keihn carb. I don't know what size jets are in it. I did the plug test. I got it wound out in fifth gear and shut it off. The plug was black and wet. It doesn't idle. While riding thru the trails you would have to keep reving it to atleast half throttle constantly. Then when you would have a part where you could really get on it It would sputter until about 1/4 of the way through 3rd gear then it would run good. Sorry I don't have anymore info. I haven't had a chance to even look at it until today.

 

I forgot I'm running a b8es and the second plug was a br8es.

 

Here, read this! Everything you ever wanted to know about jetting your Keihin carb.