smoke under acceleration

[Striker]

Hello and good day to all. I have an issue I am hoping can be fixed. The other day when I was following a friend on the freeway I couldn't help downshifting and accelerating a little past him. But he later told me that when I hit the throttle smoke, (described as looking grayish) puffed out the exhaust. There was also a puff when I upshifted under acceleration as well. But under normal riding there is no smoke whatsoever. So I am curious what could be causing this? I have checked and the oil level has not dropped one mm from the last oil change 800 miles ago. Any thoughts and ideas would be most useful. Thank you. (my initial thought is that the bike just needs to be tuned.) Also, I bought new spark plugs but lost the manual to the bike. Anyone know the gap?

[Harvy]

Grey smoke = unburned fuel.
Blue smoke = burning oil.

AT a guess its running rich at higher throttle opening because either/both the needles or emulsion tubes are worn, allowing too much fuel through.

Harvy

[andyb]

Smoke means something's burning.  Odds are it isn't brake fluid nor clutch fluid.  If the oil isn't changing level, then it's fuel.

Sounds rich.  Rich smoke is described as brown, black, or grey, depending on who's seeing it.

Check emulsion tubes (needle jets), check for needle wear, check that the choke isn't sticking open, and if it's always done this (but you didn't notice it perhaps) check the main jet sizes.

[Arnie]

Spark plug gap - 0.8-0.9mm (0.031-0.35") according to GSYM

[oldktmdude]

Smoke means something's burning.  Odds are it isn't brake fluid nor clutch fluid.  If the oil isn't changing level, then it's fuel.

Sounds rich.  Rich smoke is described as brown, black, or grey, depending on who's seeing it.

Check emulsion tubes (needle jets), check for needle wear, check that the choke isn't sticking open, and if it's always done this (but you didn't notice it perhaps) check the main jet sizes.

Also check your air filter. If it's restricted, it will also cause it to run rich and blow smoke.

[Striker]

Well I know that the air filter is getting pretty bad, so could be richening the mixture. Trying to decide if I want to make the switch to K&N.  Just changed the plugs and wow! It's like a new bike. Feels like I just gained 10 horses just with that. I'll check the needles and jets to see if that's the issue.