Problem With A 2 Stroke

[Evan]

Ok we have this 01 KTM 250SX that seems to be having some problems. We though it was the plug but changed it and it didnt help. Took the carb off and cleaned it and it appeared fine, a little bit of trash was in the main jet but we cleaned it out and still didnt change. The problem is it runs strong in 1st and 2nd but when you go to 3rd and put it under a load really, it cuts out. Anyone have any idea what this could be? It almost sounds like it is leaking air around the intake but there is no holes or anything.

blown gasket mabe?

[Sandragggen]

Spray a little either around the intake, but not in the airfilter. If it revs up you have a leak. Please note when I say a little either....for you don't want to blow it up.

[-=Skot=-]

maybe the reeds

[Evan]

ok we have done everything that we can think of. checked reeds went back to stock jetting cleaned carb several times. several new spark plugs cleaned filter, checked intake for holes etc Went to the deale today and told him the problem, and he thinks its the cdi box gone bad. I am not so sure but it seems that is the only thing it could be. Anyone else have any suggestions b4 we go buying something we dont need. This is a problem that has only started about halfway through a plug, we made no changes, whatsoever, he has been racing it and when he started racing it, he put a new plug in it, and for the first race it ran fine, like a bat out of a cave, the next race it started doing the problem, on holeshots, but not in the race, it would sputter and gurgle all the way to the first turn, well after that race I put a new plug in and it seemed to fix the problem to me but he says it hasnt, I dont really know since its not my bike I dont know how it normally runs. So this problem has arissen from just between plug changes, the KTM guy says that they have had different plugs fry cdi boxes but I dont know how.

BTW KTM is coll they come with all kinds of aftermarket stuff, bars reeds, airfilter, rims etc and they also have a very finely detailed work manual that comes with the bike along with a parts sheet that shows where every part is and the part number. Even come with stickers and numberplates to put on. Maybe honda should take a lesson in this.

clean all of your electrical conections first..make sure the spark plug cap is tight. if you belive it's jetting try playin with the needle. i would drop it a notch and see if that clears anything up.

[airheadedduner]

As far as fuel, cutting out means lean. Check if you have a gasket out somewhere or a clogged jetting circut. If there is no problem there then it is electrical.

[big-guy]

Check the exhaust for a restriction. That sort of thing will make you pull your hair out.

I don't think it's electrical if it only cuts out in 3rd gear, that'd show up in any gear.
But if the dealer will let you try a new cdi box before you buy one, it's worth a shot.

Big-Guy

ok dude had this same problem with my blaster the other day. i went from the stock fule mixture to 32-1 ratio ( stock is 18-1) and it did the same thing it boged in 3rd up but 1 and 2 were fine. u had to drop the clip 2 noclec and fix the piolet and main jet now she pulls hard throught the whole band