Starting Problems on 93 KDX250

[Crimeidy26]

Ok guys here goes... I rode the bike last weekend and it cranked as it has in the past on the first kick...Tonight i installed a new clutch cable as the other one was worn out and i went to crank the bike to check to see if i had the clutch adjusted right and nothing... Me and a buddy kicked it for an hour and nothing except for a few bruises on the shin from slipping off the kick starter. I checked the plug and it was somewhat wet so i know its got gas, i leaned the bike over and it ran out of the carb overflow under the bike, I took the spark plug out and kicked the bike over and it was sparking blue lightning bolts. I then adjusted the air screw in every direction and then put it back to where it was when it was running fine and still nothing. I'm baffled and its making me hate this thing more and more. I've never had a starting issue with this bike it usually starts on the first kick or second kick everytime, and it rode beautifully last weekend. Any ideas as to what it could be causing it not to fire because i know its got got spark and gas and im assuming air because the air screw is back to the original location and i've moved it in every direction. I'm stuck any ideas would be appreciated. :bang: :bang: :think:

 

[KIWI KDX]

have u tried crash starting it?

 

[Crimeidy26]

I haven't tried roll starting it, but i did spray just a squirt of starting fluid in the spark plug hole and it fired up for just a second and then when i tried 2 give it the slightest bit of throttle it died and never even sounded like it wanted to fire up again?? I can't figure this thing out to save my life.

 

[dirt bike dave]

Did you replace the plug with a new one?

FWIW, worn or cracked reeds can make a bike nearly impossible to cold start. But try a new plug first.

 

[Crimeidy26]

OK. will try that but the plug i was using only had 1 ride on it and it looked fine and was sparking beautifully... I'll try a new plug and see how that goes this evening. Thanks for the help.

 

[dirt bike dave]

Hmmm, if the plug was that new it could be something else. But since that is so easy to rule out, I would still try a new one first. Once the plug gets wet, it can spark fine outside the cylinder, but inside the combustion chamber it is a different environment (more pressure, more moisture).

If the plug and reeds don't solve the problem, other issues could be low compression due to worn rings and piston (but weak starting from this usually comes about gradually), or possibly the woodruff key holding the flywheel in place has sheared. This is not common, but when it happens you can get a strong spark, but it comes at the wrong time.

 

[Crimeidy26]

I was thinking about doing a compression test to rule out compression issues but i was thinking the reeds could be worn out...I tried a brand new BR8ES and still nothing... It acts like it doesn't even want to think about fireing...I guess im gonna have to do a tear down and see what this thing is doing wrong, i didn't think about the woodruff key...When i was kicking it last night i kicked it one time and it made a clank clank noise sounded like metal on metal but it only did it one time and i never heard the noise again. I guess we'll just have 2 take the engine apart to diagnose the problem. Because i know of nothing else to do to it to make it fire other that spark gas and air. And its got spark and gas and air..I guess it could be worn out reeds or low compression but i'm not thinking its low compression because it still feels the same as before when trying to start the bike. I'm just puzzled at this point.

 

[Crimeidy26]

Well.... i just took the carb off....AGAIN... cleaned it out let the jets soak...BTW pilot is a 42 and Main is a 160... Put it back together tried kicking it and nothing so i the took the spark plug out and sprayed just a touch of carb cleaner in the cylinder and she fired right up...But now after doing so it seems as tho the throttle is hung about 1/4-1/2 open..im assuming i just twisted the cable and it is pulling the throttle open at this point but none the less it's back alive. I believe the cable to be original or really really old so i 've got a new one on the way to fix this problem...Thanks for all the help guys i really appreciate it.