Reply With QuoteProbabkly the engine temp sensor.
I have an 04 XB12S and about 3 or 4 weeks ago my bike started to misfire at high rpms and then seemed to get worse as it eventually started to misfire while crusing on the interstate and around town. Last night I changed the spark plugs to to NGK Iridium 9's thinking it would be the fix but it didnt and actually worse. If I start it up cold it runs fine and even after running a few minutes I can give it full throttle no problem through the upper RPM's but it seems once it gets warm or after running for 15 minutes + it starts to misfire and backfire. I'm thinking it's got to be the coil/ignitor or the plug wires. Anyone had an issue like this?
Probabkly the engine temp sensor.
Why would the engine temp sensor have to do with misfireing?
Did you do any mods around the time this started?
Edit: He's thinking a bad sensor may be telling the ECM the bike is overheating & causing it to go into skip-spark mode.
Nope no mods. I did notice some type of control under the air filter cover that looked like it had a cord that should be running to it that was complely missing the cable when I was changing the spark plugs. It's been like that since I bought it though so I doubt it has anything to do with the problem. Does anyone know what that is or its significance? It cant be too important because I've put over 7,000 miles on the bike with that thing disconnected.
I also ordered new plug wires and a used coil from a firebolt to see if either of those is the problem. Hopefully be here by friday.
I figured out the control under the filter cover controls the variable exhaust and I have the buell race exhaust so that explains why it isnt hooked up. Anyone have any new ideas. I'm betting its the wires or coil. Rode yesterday and it cut off on me like 4 times and I just had to sit and wiat for it to cool down before it would start up again.
I wished I had a good answer for you but I don't. The only scenario I can think of that is similar is an old Toyota FJ-40 I used to own. It would go to missing once warmed up but ran perfect cold. It ended up being an intake leak on the manifold.
It could be the coil. That is an old school symptom. Once warm it starts breaking down. Hopefully once you do the new install(coil) your problems will be gone.
Good Luck.
I switched out the coil and wires this weekend and had the same issues. So now the only other think I've found was something about an ignition control module but I'm not sure if its even a real part. I think it is in the ECM which I believe is like the computer for the entire engine and I really dont wanna drop ~$250 for something I'm not sure is the problem.... bump for help?
How bad exactly is the misfire? Is it constant or every so many seconds, or once a minute? Does it seem to be running very hot?
I bet it's too lean, especially if you have mods like race exhaust and are running stock fuel and timing maps. I'd flash the race maps to it and do a TPS and AFV reset and see if that helps.
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