Motorcycle Repair: 1988 Yamaha Virago 250, yamaha virago 250, combustion chamber

Question
Hi,

I just started to clean out my motorcycle and i started some general maintenance, whereas my bike hasn't been started in a couple of years. The main thing that had to be done was a cleaning of the carb. After this was complete, my bike now backfires once in a while and blue smoke comes out of the exhaust. Any ideas? I believe i have to adjust my air intake valve, but i'm not sure.

Thanks for any ideas that you might have!

Matt

Answer
Matt,
Sounds like you are running a bit rich.  Be absoulutly sure you floats are set at the correct hieght, there is a spec for these in the manual.  It is very easy to bend the tab by accident while dissasebleing and cleaning.  Be also sure that your needle valve is not sticing open and letting exess fuel into the float boal.  Backfiring commonly happen when liquid fuel makes it's way past the combustion chamber and into the exhaust system and them explodes  from the heat of the pipe.  This can be caused from excess fuel and/or incorrect timing.

Hope this helps,
Mike