[jkv45]

Originally Posted by austinninjabill

It was actually a 400, not a 250, I was 14 years old when I owned it, weighed all of 125lbs, and it scared the hell out of me compared to the Suzuki RS 125 I moved up from. Sold it and moved down to a CR250 for a very short while before I got interested in other things.

It has a stock exhaust.

The shims thing makes sense now that you've explained it. I am guessing that there are also these adjustable needles -- position 1, 2, 3, etc. -- that can be turned to be higher or lower right at the exposed part of the needle in the venturi without having to pop the top on the vacuum diaphragm?

Everyone seems to be between 108 and 112 on the main jet, so I am going to split the difference and go with a 110 ands cross my fingers.

Same with slow jet: everyone's between 38 and 42. I was thinking of a 40 just to be on the rich side a bit, unless you think that is overkill.

All I know is what worked for us.