I have been going around and around trying to get my bike to run right. 2005. I have owned it since 2007. Always ran fine until last winter. I did all the maintenance (probably too frequently).
It started out with a combination of spark and carb problems. Reved fine in neutral. Intermitent poor running and bad gas mileage. I would get 50 highway and this dropped to 28-30 mpg. Sometimes it ran fine. Had some fuel leak back into air box. When running bad I would get power loss and some missing at 4000-4500 plus.
What I did so far in order:
valve adjustment(didn't really need it and did nothing)
rebuilt carbs(this helped)
disassembled and cleaned gas cap and gas shutoff valve(might have helped)
Cleaned stock aircleaner
new fuel lines, vacuum lines on carb etc
*I should say now that the fuel system was very clean and so were the carbs*
replaced lost gas tank bumper(I think this might have caused a high speed miss)
replaced plug wires
replaced spark plugs(old ones looked near new and fine)
*the above 3 items did get rid of a high speed miss at 5000+rpm*
After all this the bike runs good half the time. I think my gas mileage is still poor(been flogging it in frustration). The other half it has lack of power above 5000 or higher.
I tried running it with the guts out of the gas cap and the fuel valve on prime. No effect.
Removed the air cleaner. RUNS MUCH BETTER
I decided the air cleaner is bad even though I kept it clean and it looks fine.
Replace with K&N. Runs even worse. 5000+ rpm when hard accelerating BAD. Will slow accelerate OK to 80 mph+ but still not running great.
Removed air box cover. Made more noise ran even worse.
Removed air filter and ran with air box cover on. runs pretty good.
If this was a newer car, I would think a gremlin sensor or something. I don't get the removing the air cleaner at all. I actually tried that back at the beginning and it did nothing.
Should I vent the stock air cleaner and trade it in?
I really thought it must be spark(electrical) until the air cleaner experiment. No clue what would do this. What say you?
TIA Sam