I have a KX250F 2004 that won't start. It is all stock and I haven't ridden the bike in about 4 months. I got it out of the basement the other day and it will not start. I think I have tried everything (what little I know). Please help.

 

Did you check for spark? If it has spark and won't start, if it was in an area where a there are mice, you may want to check the airbox out. I've had a few mice get into my my bikes already. One bike was a 2000 KX85. They made a nice mess of my airbox and carburetor. Not sure if this is the case but it's something you can check.

 

How do you check for spark and yes it has been stored where there may be mice. I'll have to check the airbox condition in the morning. thanks

 

To check for spark you need to remove the spark plug from the cylinder head, then put the plug back into the spark plug boot.
You will then need to rest the spark plug on some metal area of the engine, like a bolt somewhere on the head. Then you need to kick start the bike and watch the electrode on the spark plug to see it is is sparking when your kicking it over. You may have to have someone watch for you while you kick it over, or vice versa.

I think the spark should be a bright blue color for good spark?

If you've got spark and airbox is OK, it could be dirty carbs.

How's the fuel? I'm not familiar with your model, is this a 2 or a 4-stroke. If it's a 2-stroke, is the mixture correct?

 

The airbox was ok. I had just replaced the spark plug cap and ingition coil about 4 months ago. The wire from the ingition coil had to be screwed into the top of the spark plug cap. I checked for spark like you said and there wasn't any. So, I twisted the wire a little bit more into the spark plug cap and tried it again and got some spark. Thanks a whole bunch b/c it started up in about 3 kicks. Oh, and it is a four stroke. Again, Thank You.

 

I'm glad to hear you got it running and didn't have to take it in. Plus your learning something each time you work on it, feels a lot better that way.