Ok so i have a 2003 kfx 400 and just recently it it wouldnt start with the electric start button soo a few times i ended up push starting it in the bush. Now it wont even think about firing with the starter.... So i did some trobleshooting and heres what i came up with. The batt is fully charged and putting out the right amount of power, the quad will turn over and turn over and turn over with loads of speed, i pulled the plug and there is plenty of spark. the thing is that it will turn over all day holding the button but wont fire... but as soon as you push it and the tires turn over the motor it fires right up and will run like a top! If you can help me in any way that would be much apprecited!! thanks!

 

Push starting will actually give you a bit more engine turning speed than even a fresh battery and starter, so if you can start easily with push but not the starter,I would look at your valves. Too tight or too loose,and they can be a bear to start electrically,but seem to do fine when pushed, making the motor spin faster,and that seems to help fire it off. My son's 300ex was a real pisser to start, you had to play with the throttle, and crank a lot to fire off, one day I just got tired of it and checked the valves just for the hell of it, exhaust was being held open it was so tight, reset the valves, and it made a world of difference. If you are checking valves, just take a quick look and make sure your timing marks line up, maybe a stretched cam chain is starting to cause problems as well. Keep us informed what you find, and good luck.

 

Thats true that your gaining more engine turning speed push starting it. the valves and timing chain were done recently and have only put a few hours on the bike since that. my lines line up and spacing is correct...any other thoughts? thanks!!

 

check the wiring from the battery and the starter. i had the same problem last year and i put a lot of new parts and found a broken wire in the wire lume.

 

so a few months ago i had replaced the timing chain and put new spacers in for my valves since they were sloppy. Yesterday i decided to just double check the spacing on my valves since 95wolv thought this might be the problem... when i got the motor to TDC i could get a .150 under the exhaust and the intake was so tight that i couldnt get anything under it. This i dont understand because only a few months ago we spaced them and it ran good. So here is another question for yah, what spacing are you using for your valves? Ive been told to run .150 - .200 on the exhaust and .100-.150 on the intake...sound right? Thanks for the help!!