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Difficulty Starting

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Hey guys, first post here in ages(can't remember old acct and pass).. Having trouble to find time riding lately with work and college and sorts.

Anyways, to the problem.

My bike (2005 KX250f) just does not want to start. Let me rephrase, it literally won't start unless I bump start it. We shimmed the valves not long ago(I ride woods only).

One thing I've noticed, whenever I am trying to kick start it, it just doesn't really seem to have much life to it. It will backfire(basic popping noise quite a bit following a kick). Outside of that, I am just clueless. I don't think it is the spark plug because that looked fine, and I don't see how it could be the gasoline.

Once I do bump start it, it runs just fine, like nothing in the world is wrong with it. If it dies on me after it's been running a few minutes, it will start back up on the first or second kick.

Any insight would be greatly appreciated. Thanks a bunch guys.

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im not sure but bump/jump starting it would casue the timing to go out of spec..cause the cam chain would jumpp

well first let see if this works prime the engine with the Ap squirt by twisting the throttle 3 times, then kick the kick starter slowly all the way to the end of the rotation for about 3 times...then bring it up and kick the kick starter really lightly until u feel the tension..go 1 inch pass that tension spot (this way the piston is at TDC and valves are closed, or close enough). then bring the kick starter right back up and then give it a nice hasrd kick like a 2 stroke...

if this doesn't work check the valves again and check to see if the timing is correct...also u mensioned that when u kick it, it seemed like there was no resistence...i would check the compression...have u done anything else to the bike?

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Nothing outside of the standard maintenance. I have no reason to really believe that there is a compression leak. My bike has always been extremely easy to kick.

When I say that that it doesn't really seem like theres much life to it, I mean just by the sound. It's hard to explain but being around dirtbikes most of my life it just doesn't sound right. It doesn't really even seem to be trying to start, best way I can explain it.

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I had the exact same problem last week with my '05 KX250F. All of a sudden it wouldn't kick start. It would bump start first push and while it was warm would kick start first kick. If it cooled down a little bit it wouldn't kick start again. I checked my valves not long ago and they were right on. I decided to check the valves again and found the left intake had zero clearance. Once they start to go they can go fast. While I was trying to kick start it I noticed that I could smell gas like it was flooded. It also had a loss in compression. With the left valve hanging open of course it was flooding and had less compression. I have 80+ hours on it so I am replacing the valves and also piston and rings.

Check your valves even if you think they are fine.

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Yes I second or third that.Check your valves.Bump starting a bike does not jump the cam chain.The only way this would happen is with a bad tensioner and the bike would jump timing anyway.

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jetting?

yea i would assume it is, if he says that he's valves are on point...but i would check the valves again...

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Sounds like stale gas to me, especially since it starts fine after running a bit. Try draining the carb ane let new gas form the tank fill it up. Mine will do that if it sits for more than a week. Now I turn off the gas and let it run out after each ride.

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