I have a 2003 xb9s with race exhaust, ecm, and k&n. Last fall I was riding and it lost power and was making a metallic sounding ping if I opened the throttle to try to accelerate. When I pulled over it still idled but a little rough and was a little smokey. This spring it will not even start. Here is what I have diagnosed so far… It seems to turn over fine, the fuel pump moves fuel (I didn’t put a gauge on it), It looks like fuel is misting in the throttle, I replaced both plugs and checked the easy front one for spark and it looks strong, I checked the timing and it is correct, reset the tps, no trouble codes. After checking all this and it still not running I decided to put some gas in the throttle and see what happens. It fired for a few strokes, backfired a little when the throttle was cracked (prob. Extra gas in throttle?), and smoked a lot. I did this a few times and it was the same every time. From what I know, I have a hunch that maybe a ring went. Also, when I pulled the old plugs one of them had half the gap of the other. Any ideas? Thank you!
Just guessing. An engine needs...fuel, air, compression, spark. You have everything but fuel when you need it. It fires when you dump fuel in the throttle body but won't run, you've got fuel delivery problems. I'm betting it sat over the winter and clogged stuff. Not sure where ya get the idea of a broken ring. It will still run with a broken ring if it doesn't sieze, might run ****ty, but it'll run. As always, if I'm wrong please let me know. Wayne
do you still have the stock ecm, if so try putting it back in and see how it runs. its worth a shot. my bike 2 weeks ago started firing on one cyclinder and i went threw the diagnostics to see if i can find the problem, out of a whim i threw my stock ecm in and it ran perfectly.
i'm not ruling the fuel delivery out yet totally, but it looks like gas is being injected when i look in the throttle. When i do get it to fire with pouring gas in the throttle it smokes ALOT. Enough that crankcase oil getting up into the combustion chamber seems pretty possible. plus fuel delivery doesnt really explain it running bad last year.
or there could be a intermitten wire somewhere in your wire harness that could really caus alot of your troubles.
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