Topic: white smoke, could it be from my air box boots leaking?

[elcid]

I have a 78cb550 with 8k original miles on it. Everything runs great except all this white smoke. First of all does white smoke mean too lean or too rich? I looked and I can see 2 of the 4 rubber boots for the airbox have holes or tears in it. Could this be a cause for all the white smoke? I noticed that I don't seem to have enough "power" either when I accelerate. I had a piece of crap ratted cb550 with oil leaks that had 30k miles plus on it & the torque seemed a lot stronger.

Or maybe do I adjust the mixture screws? if so, how much & in which direction? Thanks!

[CB750F2]

G'Day. Are you sure the smoke is white and not bluish white? Black smoke indicates a rich mixture, bluish white indicates oil and white indicates condensation. I wouldn't think that the damaged rubbers between the airbox and carbs would directly cause the smoking but if they have been damaged for some time dirty air would have been sucked into the cylinders causing wear in those cylinders,pistons and rings.
I would repair/replace the damaged rubbers and do a compression check with the bike at normal running temperature. I would also check the breather line for blockage. I have had no experience with your particular model - CB750 F2 is my ride - but my comments would still apply. The above would be a starting point in finding your problem. I am sure others will help out. Regards, Pat

[TwoTired]

1 - Tune up the bike
2- Clean/replace the air filter
3 - Clean the oil breather filter at the bottom of the air box.

This should improve your performance issues.

White smoke is condensation steaming off from inside the mufflers.
Check the low point of each muffler and find the "weep" hole.  Make sure it is clear so water can drain out.

Run the bike about 20 minutes on the freeway get the entire muffler hot.  This makes all the water in the exhaust evaporate.  And, the white "smoke" should stop.  Until another cool down cycle.  Condensation will again form inside the mufflers, drawing humidity from the air.  It will take longer runs to make this evaporate during the colder months.  I you don't thoroughly heat the mufflers, water will build up.  The muffler drains should limit the buildup, provided the inside of the muffler is clean.  Soot will absorb water like a sponge, and only heat will make it go away.

Cheers,