ralfyguy wrote on 11/09/12 at 08:54:14:srinath wrote on 11/09/12 at 08:06:07:Tom K wrote on 11/08/12 at 05:46:45:Serowbot wrote on 11/07/12 at 09:46:26:I was always taught,.. smoke when running is rings,.. smoke upon start-up is valve stem seals...
Me too. Smokes all the time. I took it out last night for 20 minutes and still not much improvement.
Did you get the assembly lube all burnt off ?
Is it definitely oil ? or you running rich ?
Cool.
srinath.
Mine is doing something more weird than that, and that since years. When temps get lower in winter, when starting cold I always let it run for a minute. No smoke at startup, but then after half a minute of running it starts blueish whitish smoke for another 10 seconds then quits smoking. It only does it in winter, never in summer, and oil consumption is negligible.
Maybe ... maybe not that water vapor thing serowbot said.
This is a litte more serious scenario.
Valves when cold have a clearance lets say 1 thou. After the motor fully comes up to temperature, that will increase usually but by a very small amount, say 1.25 thou.
However the components all do not heat up @ the same rate.
The parts that get the hottest fastest are the exhaust valves, cos the exhaust is streaming past its stem. Since that is 1 heat path and the other path is the head which typically get to temp the slowest, you can easily have a valve staying open as the heat builds ... usually may not be an issue ... but worth checking your clearance, and if you're tending close to the limit on the exhaust, go ahead and set it toward the high end of the spec and you could see this go away.
Cool.
Srinath.
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