white smoke and back fire on startup

[mordantmonkey]

I get white smoke out of the left muffler when i startup, it's not that heavy and it clears up after the bike warmsup. I also get intermittent backfire (sounds like the right side but not sure) about 3 or 4 times while the engine warmsup. it seems that the backfiring has to do with the carbs since i have to adjust the choke and idle in increments as the engine warms up.

Is this particularly bad? i mean, should i stop riding now and tear the bike apart or can i hold off until the weather forces me off the road?

[renobruce]

The white smoke is probably just condensation from being cold. The backfire might be your choke circuit... maybe needs cleaning. The next time you start it to warm it up, check to see if one or more of your pipes are colder than the others.

[mark]

The white smoke is probably just condensation from being cold. The backfire might be your choke circuit... maybe needs cleaning. The next time you start it to warm it up, check to see if one or more of your pipes are colder than the others.

Good idea. How's it run when its warmed up? If everything is O.K. afterwarm up....I wouldn't worry about it. White vapor is normal on cold start-up.

[mordantmonkey]

these problems are just during startup. after it's warmed up it runs great, aside from a rough idle (geting the parts for a carb rebuild right now). but i'll be sure to check the choke.

The white smoke just seemed kind of odd since it only comes out of the left side.

but thanks, i'll be much more at ease while taking advatage of the last of the warm(ish) weather.

[Tarbash 27]

the white smoke is probably a bad valve seal which when cold it leaks but once it warms up it seals properly. my bike does the same thing.

[tconroy]

I get white smoke out of the left muffler when i startup, it's not that heavy and it clears up after the bike warmsup. I also get intermittent backfire (sounds like the right side but not sure) about 3 or 4 times while the engine warmsup. it seems that the backfiring has to do with the carbs since i have to adjust the choke and idle in increments as the engine warms up.

Is this particularly bad? i mean, should i stop riding now and tear the bike apart or can i hold off until the weather forces me off the road?

The next time you start it up put your hand behind the muffler and see if you get condensation on you hand. you should only have to adjust your choke on warm up.You might try some "sea foam " in the gas tank and see if that helps till you rebuild your carbs.I might be doing that too.A never worked on my carbs yet.i was waiting for the weather to get worse before starting but i may go ahead and do it now.

[KEITH KRAUSE]

Yup (referring to tarbash 27 post). And the oil burning can lead to the sparkplugs temporarily fouling.
Oil in the mix will weaken the spark. A weak spark won't ignite all of the mixture. After a certain amount of unburned/raw fuel collects in the cylinder/exhaust, bang, you get backfiring. As heat increases, this will help the plugs fire better and the problem "goes away".
It will get worse, but hard to say when it will force you to repair it.

[Doctor Shifty]

Couple of different suggestions coming up ...

The white smoke on start-up can be a symptom of a worn inlet valve seal. I little bit of oil leaks past the seal when the bike is standing there and the seals are cold and hard - when you start up it burns it off. The seal is not worn enough for it to be a problem when it is warmed up. Coming from only one pipe suggests it is on that side of the engine.

Backfiring can be a symptom of a hole in the muffler or pipe, usually towards the engine. This issue will mostly show up when you decelerate after giving it a bit of throttle. There will be some unused fuel in the exhaust and the loss of pressure will draw fresh air in through the hole in the muffler and it will explode.