I acquired a 2002 bike with 8K miles that was sitting for 3.5 years, I replaced the fuel lines, cleaned the carbs and the bike started ok and i rode it for 30 minutes.
A week later it didn't start and I diagnosed it due to rust in the fuel tank clogging up the carbs. I replaced the tank, cleaned the carbs again, looked inside the manifolds and noticed gunk on the valve stems.
At this point I made a terrible judgment call that I really, really regret. I sprayed carb cleaner inside the manifest to dissolve the gunk. And in an attempt to do a better cleaning job, I turned the engine over by rotating the wheel while in gear.
After about 20 minutes I attempted to start the engine and after 10 minutes of cranking it began coughing out smoke out of exhaust and backfiring. I thought it was cleaning itself out so I continued cranking. Then a massive backfire explosion happened in the intake manifolds and smoke went thru the carbs and came out from below the seat.
After some more cranking I took off the air box so I had direct access to the carbs. I sprayed a bit of starter fluid into the left carb while cranking. To my immense disappointment white smoke came out not just from the exhaust but from the air port of the 2nd carb.
I suspect in the best case I have deposits on the intake valves but could the backfire have burnt them as well? I plan to order a compression tool to see how bad things are but i'm afraid an engine rebuild may be required which is way beyond my abilities and sounds like a really expensive job for a shop.
I would appreciate any suggestions, though I should have consulted you guys before i fked things up. Please don't be too harsh, i'm already really devastated over it.
