More information on smoky starup

Hi everyone.
Well, from a cold start, starts first kick, then let it idle for 30 seconds at 1500, then open throttle and hold at 2500rpm, still no smoke
then crack open throttle up to around 400rpm quickly, here comes the white smoke pouring out on the left pipe only, all while non in motion yet

any ideas, could it be the left piston rings are sucking oil up and in to the combustion chamber upon the rapid pressurization cracking up to 4000rpm?

on is this a head problem somewhere?
appreciate any comments

I wonder if your left piston rings are in the proper alignment. When I put new pistons in this time I stagerred the piston rings at 120 degree intervals. I put new piston rings in my 75 850 about 12 years ago and have alwayys had a smokey right cylinder after a long hard ride. When I get some time, I am going to check the alignment of the rings. So far, it has not been bad enought to warrant pulling the top end off. I have done two valve jobs thinking that would cleanup the problem. It is still the same. Years ago I bought a 72 750 Interstate that had been left in a field for 20 years. I paid 20 dollars for it. The valve stems were soft from the factory and thus the bike quit running. I just pulled the head and had new valves and guides installed. I never messed with the piston rings. I put on the old scholl copped head gasket and have since torqued the head tree times. No smoke. No leaks. That is why I think I screwed something up when I lined up the piston rings in the 850.

Classic test for bad rings is to test compression, then add a teaspoon or so of oil into the cylinder through the spark plug hole and retest. If you get substantially increased compression, you've got bad rings.

My left cylinder reads 120 PSI dry, 160 wet. Rings are on the workbench awaiting snowfall - i.e., "wrenching season."

Of course, there can be MULTIPLE causes.

Good luck.

a leaky valve guide seal will show on a high rev decel

crack open throttle up to around 400rpm quickly, here comes the white smoke pouring out on the left pipe only,

Click to expand...

I mentioned this on another thread, please consider the possibility of too much oil in the oil tank which goes down the breather into the back of the airbox. The airbox is sometimes wet at the bottom with oil.

Crack the throttle open for maximum vacuum or suction of oil into the engine. Oh and if it is on it's prop stand the oil goes to the left side of the bottom of the airbox and therefore into the LH carb.

Worth checking.

Ok, thanks everyone for your replies. I think I got the smoke at startup figured out.
Talked with Heinz Kegler, he told me to start it, hold idle at around 1300 for a good thirty seconds then put it in first and pull away while using
as little revs as possible, shift to second around 2500, and let the motor warm up slowly before applying any rpms above 3500.
He said I am sucking cold crank oil when I would rev the motor too soon after startup.
I have been following his instructions and I now have very little smoke leaving the pipes in the first minute of riding.
thanks again to everyone who replied