I have a 91' lt250r. I just got it back from getting the motor totally re-done, I need help jetting it now, I got it about half way broke in. I am about 300 ft. or so above sea level, I mix klotz supertechniplate 32:1. It is bored .030 over, has boysen reeds, and a FMF fatty pipe and FMF silencer. Right now I have a 280 main jet and I am pretty sure the needle is at the stock setting. It doesn't rev out when I give it the beans, it only revs so far then kinda blubbers and doesn't rev all the way out, is the main jet too rich? what size Should I go to. It starts great. Also, when I try to adjust the idle with the idle screw it doesn't idle at all after it is warm till you screw it all the way in, why is this? how can I fix it? Any other jetting help would help me out a lot.


thanks, chuck

 

The best thing to do is toss the stock carb. Its junk. Call keihin and they have the perfect carb for you.

 

Sounds like your too rich get,2-3 sizes smaller on the main jet,if not more,it really matters how rich it is.

 

I went from a 280, to a 270, to a 260, now it revs out alot more but I think it is still running a little rich, I can tell it doesn't rev all the way out still, I am going to leave it like this for a little while till it is broke in a little more. How much of a differance does a new carb make? low, mid, top smooth?


chuck