A lot of blue smoke from left cilinder

[hein weijers]

When I start my rebuilt 750 cc, 277 degree XS (cold) , it produces a lot of blue smoke, but only out of the left cilinder. Within a minute the smoking stops and everything seems ok. As far as I can see, there is no oil consumption. Question: why only the left cilinder and why does it stop completely within a minute? Anyone with the same problem?

Kind regards, Hein

 

[Luke4554]

Blue smoke is oil .. could be that theres a little getting by a seal or a ring or something after shut down. Its probably being burnt initially then when everything warms up and expands it probably is sealing itself up. Thats what i would venture to guess. I wouldnt worry about it unless i bothers you. It is 30 years old .. if thats all of the extent of it id say roll with it.
Luke

 

[hein weijers]

Hi Luke,

It wouldn't bother me if the barrel and pistons were 30 years old, but they are brand new! Also the valve seals are new. It is also quite embarrassing to leave home under the cover of a blue smoke screen when I go for a ride.

Hein

 

[urbandork]

how many miles on the new rebuilt motor? maybe the rings havent seated completely.. had the same problem on my 750 kit... 500-600 miles later no smoke on a cold start up.

 

[hein weijers]

I think about 400-500 miles. So I still can hope for improvement?
Did you also have the smoking problem on the left side? I understood that the lubrication is not symmetrical, due to the position of the gearbox.

Hein

 

[Luke4554]

Hi Luke,

It wouldn't bother me if the barrel and pistons were 30 years old, but they are brand new! Also the valve seals are new. It is also quite embarrassing to leave home under the cover of a blue smoke screen when I go for a ride.

Hein

true that... i just noticed you said 750

 

[XSLeo]

My 750 on cold starts blows lots of white smoke on the left side. Only about 200-300 miles. I hope it gets better. I need to do some carb work, so it may be from there too.

 

[PhatTony]

Hein
What kind of oil did you use to break in the motor? I used a synthtic before I knew better and the rings never seated right. Always smoked on start up and cleared after a minute or two.
Either way you have oil getting into the cylinder after you shut it off. It's going to be the piston rings or something in the top end like valve seals, head gasket, or o rings.

 

[urbandork]

I think about 400-500 miles. So I still can hope for improvement?
Did you also have the smoking problem on the left side? I understood that the lubrication is not symmetrical, due to the position of the gearbox.

Hein

yup left cyl... but after doing the baking soda trick and riding it for about 500 to 600 miles the smoke on cold start up gradually went away over time. i also tried my best not to rev the motor up to high while breaking in and was on and off the throttle/engine breaking in order to attempt to get the rings on the left side seated.

 

[hein weijers]

Thanks guys, I think I'll wait with conclusions until I've made some more miles. Still puzzeling that it is only the left cilinder that smokes.

@urbandork: WTF is the baking soda trick???