'03 KX100 quit and won't start

[carl1864]

My girlfriend '03 KX100 ran like a champ, started like a champ, etc. Last time we were riding, there was a situation that may or may not have contributed to the problem.

During a riding break, her fuel petcock got turned off, and she started riding with it off, until it died a short distance later. After turning it back on, the bike ran shortly, but then died again, and we have not been able to get it started since.

I thought it was just a fouled plug, but we replaced the plug (used a br9es), and no luck. Pulled the plug and kicked it, and we are getting spark. Fuel is flowing through the petcock just fine. Tried starting fluid, tried pouring a little gas in the spark plug hole, can't even get so much as a sputter.

Haven't looked at the air filter, but don't see how that could be it. Like I said, it went from running like a champ, to not running at all in an instant. Wondering if it could be a carb issue like its not getting any gas, but don't see why that would happen so suddenly, and why it wouldn't at least give a little sputter when I poured a little gas in the spark plug hole. I've used a mirror to look in the spark plug hole, it seems pretty dry in there, so its not flooded.

I'm puzzled, any ideas what it could be, or what else I should check?

 

[_JOE_]

If you've got good spark I'd remove and clean the carb and air filter first. Make sure you remove the jets and force carb cleaner through all the passages then blow them out with compressed air. Same deal for the jets. Some people just replace the jets but that's your call. If it still won't start I'd check the compression. Let us know how you make out.

 

[_JOE_]

Also make sure the gas is good and fresh. If it's more than a month or so old drain the tank and fill it with fresh fuel before reinstalling the carb.

 

[2strokerfun]

Was she romping on it fairly hard after the petcock was turned off?? Being the pessimistic person I am, I worry about lack of lubrication during lean run. But if you still have good compression and engine turns freely and sound-free, it is in your favor.

 

[carl1864]

Well, I had completely dismantled/inspected/cleaned the carb, cleaned the air filter, tested the cdi/ignition coil with a adjustable spark guage, drained all gas and replaced fresh, tried many spark plugs....

finally did a compression check, and only got about 70PSI (80PSI when really kicking my hardest). Guess that's probably the problem right? Should have checked compression sooner I suppose, but considering I have never had this issue before, despite generally running engines for ages before ever rebuilding them.

Guess I'll be doing a rebuild or seeing if I can get away with just replacing the rings, and hope it solves the problem.

 

[BSWIFT]

You sound like you have it under control. Have fun on the rebuild.