Hi everyone, Let me first say I am new to this forum but thank you to those who started this site!

I just bought a 82 yamaha maxim 400, it was not running when I got it yesterday but after a little work I have it running, a few issues have come up. First of all my left cyclender has been spewing out quite a bit of white smoke and is backfiring quite a bit but it is an intermittent problem, sometimes it will run fine for a good while before that happens. Also it will randomly run at high RPM's and stay there and then calm down again all on its own. Anyone have a problem like this before???

Thanks all!

Hi, did you get this problem fixed ? a simular thing happened when I bought my FZR1000 with the throttle I went to take off the rpm's reved up high and the bike flew out from under me later when I checked the cable there was a bad kink in it and it locked up on me II just glad it was in a residental area and not on the road this was three years ago.

Yes, I think I have it under control now. I found that the spring that pulls the butterfly valves closed was sitting in the wrong place causing the valves to sit slightly open. However I have a little bit of white smoke and backfiring coming from my left carb. Is this just due to incomplete combustion or oil getting into the engine?

The white smoke is indicating that oil is being combusted, which means a broken piston ring or worn valve guides.