KLR 250 sputtered and died!!!

It's been making some weird noise lately, like the sound a bike makes when it's about to stall, that clunking sound, but all the time. So anyway, I left it running outside for 5 mins to get my bag and I come out and it's bogging like crazy, no power, I finally get it going, still no power and I go 50 ft and POP POP a couple backfires and it dies! Now I push it back to my house, kick it over a few times and it will run for a few seconds and die. It was running fine up until then except for that noise.

Any thoughts? I don't even know if the noise is related.

So, it goes from clunk clunk to pop pop?


Yea, I don't know. I'm thinking it's just running way rich and choked itself out at idle, but I'm pretty sure I let it idle longer than that on the trail the other day. I don't really know. I might work on it today in the pouring rain...

Check carb floats and for a clogged pilot jet.

I pulled the plug out, and there was a big chunk of carbon on the electrode. Would explain the lack of power and the backfiring. Scraped it off, put it back in, turned the idle screw in half a turn. Will see how that works.

No word on the weird noise. I was thinking it was top end but checked the valves which are in spec and don't see anything weird under the valve cover...maybe problems in the piston? Loose wrist pin? Don't feel like tearing it down but it's probably due for a rebuild anyway at 14kmi...

Assuming the spark plug didn't fix it...

In my experience backfiring is the result of a lean condition, possibly a clogged pilot jet or the screen on the fuel petcock valve is clogged. You have fuel in it right? (been there)

As for the noise, check that your timing chain is tight. These things are notorious for the automatic adjuster going bad resulting in the timing jumping and killing the motor. Usually right before that happens the chain will start slapping around causing a racket.

I had a simular experience to my 95 KLX250r. I drained the bad/old gas out and, wah-lah, it fired right up and hasnt missed a beat since.

You know what, the timing chain did seem a bit loose to me when I had the cover off. But I couldn't find any sort of spec to tell how loose was ok. How loose is ok? It wasn't "tight"; I could move it maybe a half inch pretty easy iirc. If I just pull out the tensioner will I be able to tell if it's gone? The manual doesn't really help too much.

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