I am about to give up - problem w/ 2002 KTM 300EXC


Premixer

Member
Mar 2, 2007
1
0
I hope someone on this site may be able to shine some light on a problem I am having with my 300. I have had this bike since 2003. Bought it new. Raced it for a year and then basically just been trail raiding since. A few months ago I noticed that it was starting to miss at high RPM's. It is so bad now that at WOT it spits and sputters so bad it is really not worth riding. I have also had occasions when the motor would surge like it had a leak in the carb boot area. I have no problems at low RPM and it still tractors along like it used to. If I try and open the throttle wide open for a quick acceleration it will bog. I have tried everything I know to do and am still having the problem. The plug indicates that the engine is running lean (white tip).

I have done the following:

1) New reeds
2) New float and float valve
3) Different Jets and Needles
4) Checked and cleaned the power valves
5) New air filter and new plug
6) Cleaned, cleaned, and cleaned again the carb

I even bought a brand new carb and put on it. :bang:

My only thought now leads me to the crankshaft seal. I don't know what else it could be. Is it difficult to change a crankshaft seal and do I need any special tools? Any feedback would be greatly appreciated. This thing is driving me nuts. :coocoo:
 

magneto

Member
Nov 14, 2001
179
0
Just a guess however it is a common problem for the power valve actuating pin on the 300s to get loose and cause problems similar to yours. The pin is located under the cover on the RHS of the engine. Do a search for this problem.

My next guess would be a faulty ignition.
 
Last edited by a moderator:

Shaw520

Damn Yankees
LIFETIME SPONSOR
May 14, 2000
1,082
6
magneto said:
My next guess would be a faulty ignition.
Agreed,... its nice to 'borrow' an ignition from another 300 before wasting the money on a new one, just to find out that wasnt it.
 

Roost1

Member
Nov 27, 2004
6
0
Make sure the spark plug cap is securly in the end of the coil wire. If its loose or pulled out just a bit it will miss at high RPMs
 


Top Bottom