Question, smoke after top end rebuild

[rwcfrank]

Hey everyone, I recently finished my 78 GS 750 with a 850 cylinder and a valve job, seals, regrind, gaskets everything. I have run the bike about a dozen times with no issues. It runs great no smoke smooth idle everything right. Yesterday I went to start it after about a month of sitting. I noticed the petcock was leaking a bit but it seemed to stop after I moved it a few times. I checked the oil site glass to be sure the fuel didn't get into the oil and it looked all good. When I started the bike I got a big puff of smoke, It was hard to tell if it was extra fuel or oil but after a second or two it went away and the bike does not smoke at all once underway. Could this be a one time thing? Other than stem seals is there any other thoughts on what may have happened? I will be replacing the petcock. Thanks in advance for any opinions.

[Agemax]

sat for a month, full choke,cold start, a puff of smoke is nothing to worry about

[Seana23]

Hi babes, i Agree with the last post...
Slightly deteriorated fuel in float bowl probably caused it, when the fresh stuff came through, the smoke cleared...
Sounds like you did a good job. Well done.

Happy riding.
X

[rwcfrank]

Thanks for the advice, perhaps I understated the puff and have now decided to describe it as a medium size cloud.....

[tkent02]

What exactly have you done to seat the rings?

[hampshirehog]

Was it definitely oil smoke? White or white with a hint of blue. Or was it more like steam - condensation (did it 'melt away')?

[rwcfrank]

It looked like white and blue to me and dissipated quickly in the air. As for the seating of the rings I have not had a chance to run them in other than the short runs around the block to check for leaks and retorque some fasteners. I have no over revved it I know that for sure.