Re-ring problem

[rwcfrank]

My 750/850 is smoking too much after a head rebuild and ring job. I can only surmise that it is a ring problem. IS it as simple as pulling the cylinders and head, rehone the bores, add new rings and reassemble? Can it be anything else? Smoke excessively at high revs and on decal. New top end with valve job, seals etc.

[Badooka]

It very well could be- possible they didn't get the rings oriented correctly or maybe even got them in wrong. If it's relatively new and no damage, you could do a light hone and I would spring for a new set of rings since your already in there and then eliminate any possibility of future issues. If budget is a problem, inspect the current rings and make sure the top ring is indeed the top and right side up. A good break in oil will not hurt. It is normal to burn some oil for the first few hundred miles after a job but then you should not be burning any at about the 1K mark- it will steadily decrease as you break in the new rings. Good idea to carry a quart-

[esmithers]

New top end with valve job, seals etc.

I would make a note that rings and valve seals go out causing these problems. if both have been replaced.. some where a seal got pinched or rings were not staggered.

is this heavy blue smoke or light white dusty smoking.

[rwcfrank]

Heavy blue smoke.

[tkent02]

Who put the engine together last time?

[rwcfrank]

I did, checked end gap, top oriented, gaps oriented, oil ring ends seated properly, fresh professional hone, bores checked for taper etc.

[chef1366]

More than likely the oil ring(s) were overlapped at the butt end.

[tkent02]

Is it both pipes smoking or just one? Not real likely you put anything together wrong on more than one cylinder.

What did you do as far as break in?

[rwcfrank]

I think I have narrowed it down to #4 cylinder. Break in was done by the new owner and not me, new rider claims all low rpm stuff. I suggested he run all rpm ranges but its still smoking.