I need suggestions on what I can do with my KX250

[Chip-N-Raven]

I have a KX250 that I just picked up and when we bought it he told us the throttle cable was kinked and when we started it it revved wide open.... It had so much compression that we had to rip off the fuel lines and pull the spark plug and it still kept revving for about half a minute... Replaced the throttle cable, cleaned the carb... fired it up and it had a slight rattling noise... we killed it and I took it over to the neighbor and when I tried to kick it the kickstart froze up..... so we rolled it backwards and it's unstuck now, and I drained the oil yesterday...I saw barely any very very fine metal shavings on my hand...maybe 4 at the most and it was finer than a grain of salt and the oil was terrible... Do you have any suggestions on what I might be able to do to get this bike running? I want to make sure everything is smooth sailing before I take it out in the desert and make sure the motor doesn't need to be rebuilt... I do want to mention that the bike did sit for well over a year because the guy we bought it from got hit by a boat and he's severely disabled now.

[mlatour]

2-strokes may share the same engine casings but have separate sumps.

The oil drain bolt is for the gearbox sump,

any metal shavings in there is irrelevant to damages on the engine's side.

 

You can get a general indication of the condition of the piston and cylinder

by removing the exhaust and having a peak up thru the exhaust port.

 

Anytime an engine 'sticks', no matter if it un-sticks itself later on, consider some damage has been done.

 

With an older bike, what could have been wrongly diagnosed as a sticky throttle cable could

have very well been an air leak, causing the engine to run lean, surge and eventualy seize up.

Partialy blocked jets (from prolonged storage without fuel treatment) could also have made the engine run lean.

 

If you intend to ride out in the desert, I'd preventatively rebuild it.

As with any older bike, tearing it down to the bare frame and meticulously

inspecting everything avoids many future headaches. Get a factory service manual, don't guesstimate any specs or adjustments.

Edited April 7, 2017 by mlatour

[MatthewMCRepair]

It seized on you? Even though you got it free again, you really need to open it up. There is no way it is going to last much longer. You are going to end up damaging more parts by running it any longer.

[Chip-N-Raven]

Yes the kick start froze.... We are planning on tearing it down by the end of the day today to see what we can find.  Anything you recommend we look out for?

[MatthewMCRepair]

1 minute ago, Chip-N-Raven said:

Yes the kick start froze.... We are planning on tearing it down by the end of the day today to see what we can find.  Anything you recommend we look out for?

I think it will be pretty obvious once you get it apart. Check cylinder wall, piston/rings, wrist pin bearing, big rod end, and main bearings. 

If you need help check this out:

 

[Chip-N-Raven]

Ours is a 1990.... That says 94-07

[MatthewMCRepair]

3 minutes ago, Chip-N-Raven said:

Ours is a 1990.... That says 94-07

Yours will be a little different, however procedure, tips, and tools used will be the same.

[ItsJuniorJ]

Trust in Matt's words. Thanks to him and his videos I know my '06 KX250 inside out. I did my first full 2-Stroke rebuild with his assistance, from the crank to the carb.