I have an 03 kx250 that's had an erratic idle and smoked like a mosquito forger. I pulled the carb (which involved pulling the seat, air box, silencer, ect....). I dropped one size on pilot and main. When I put it all back together.... PRESTO CHANGE-O !!!! No smoke, smooth idle and ran like a scalded dog ! After about 2 hours ride time, I noticed it flattening out a bit a little past 1/4 throttle. I had the clip in the very top position so I pulled the carb again and put it in the middle. When I got it all back together it was running back like it was before I jetted....erratic idle, smoke and running' like poo. I put the clip back....no change. I pulled the carb, went completely through it, cleaned it again.....nothing. I'm right back to where I started like I never did anything. Could an exhaust leak cause this ? I have a PC works pipe and an fmf shorty silencer. They don't match up great and I've noticed oil blowing out the coupling and there's grease or oil blowing out the seal around the springs. I just can't figure how it was running so great and now having it just like it was it runs like crap. Please help, I'm driving myself crazy with this one !!!!!!

Anyone? Anyone? Frye ? Frye ? Frye?Beuhler? Beuhler ? Beuhler?

8hrs on top end, new air filter, new Boyseen Pro Series reeds, fresh silencer packing. Carb is super clean, all hoses are clear. New pilot, main and power jets. Before I jetted, I figured if that didn't do it then it must be right crank seal....but after I dropped one size on main and pilot it ran great !!!!! I noticed a slight "flattening out" at about 3/8 throttle. Not bad, but the needle was real lean (top clip position) so I opened it back up and went down 2 clip positions. Put it all back together and I was right back to where I was before I jetted. So I put the clip back at top position, but it didn't help. The only thing that isn't new is the float and needle valve. I'm really confused.

Another bit of info.... I had put in a brand new plug when I jetted it and after it started smoking and running like crap again I pulled it and it was super oily. I bought a new plug and adjusted the float and there is good improvement, but it's far from how it should be.

Never "pissing" out the hose, but it's usualy wet with fuel at the end of the hose. Like if you touch it there would be a few drops worth on your fingers.

Help me out... In my manual it says float hieght standard is ......
6.5 + 1mm(.256 + .039 in) which is greek to me.
What should it measure from the float bowl mating surface to top of the float ???

Many people mistake carburation or jetting problems with needing a new top end.
I see this every day.
When I tell people this I usually hear, "We just put a new piston and rings in it".
Sometimes you can put a new piston and ring in a bike and it's fine.
If your bike is more than a few years old a piston and ring job is not usually enough.
A cylinder can look great and even pass a quick mic job.
However, unless you have experience with a mic and unless you have a decent set of mics that are properly calibrated you are better off letting someone mic your cylinder who has the proper experience.
A measurement of .0005 (4-6 times smaller than a hair off your head) or less can be the difference it a cylinder that can seal with a new set of rings and one that wont.
If your cylinder does not pass a careful inspection, then it will need to be repaired and re-plated or sleeved.
Once your top end is correctly repaired, do a compression check.
If it does read at or better then factory specs, no amount of jetting will help, really.
Also, be sure your reeds and exhaust valve assembly are clean and in good repair.
Last but not least, check your Carburetor boot to be sure there is no cracks.
Moto