my bike has started smoking white smoke not to much but constant it is a yamaha yb100 it is a single cylinder air cooled bike i took the gearbox oil out and it smelt a little of petrol should it smell like this? and the plug was black you couldnt see wet oil but if you touched it you would have oil on your hand the bike starts great first kick every time even in the morning.

thanks for the help

sound like the gearbox side crankseal is going if you can smell fuel in the gearbox oil. and it will be sucking in gearbox oil as well,best to do both sides while you are at it though

sound like the gearbox side crankseal is going if you can smell fuel in the gearbox oil. and it will be sucking in gearbox oil as well,best to do both sides while you are at it though

are crankseals a big job and will i have to split the crank i have a magneto/flywheel puller?

Webi,,,,,

Before ya go at the crank seals.

Try and make your carb a bit more lean, then go for a good hard run on the bike for half hour, see will the smoke clear.

Check the plug then and see if its still oily.

Why re-start the topic?

Webi,,,,,

Before ya go at the crank seals.

Try and make your carb a bit more lean, then go for a good hard run on the bike for half hour, see will the smoke clear.

Check the plug then and see if its still oily.

only thing with this is that it wasnt smoking when i first got it it just started when i took it for a ride and it got quite hot as i could smell it

only thing with this is that it wasnt smoking when i first got it it just started when i took it for a ride and it got quite hot as i could smell it

Go out, fill the tank, and ride the balls off it till you run out of fuel. Chances are it will run great or die. But it will settle it. I recon its full of shit. I've had 2 2strokes turn into smoke machines the first time they get ridden hard.

Did neither of em any harm.

And before this thrash check yor gearbox oil.

And after this thrash check it again.

Did you do the gearbox vent bubbles test I mentioned then that is a good indicator of RH seal failure and is easy to do

Go out, fill the tank, and ride the balls off it till you run out of fuel. Chances are it will run great or die. But it will settle it. I recon its full of shit. I've had 2 2strokes turn into smoke machines the first time they get ridden hard.

Did neither of em any harm.

ok will try this thanks i heard that if your crankseals have gone it makes the bike hard to start but mine starts easily without any choke but takes a second for the revs to respond so i wonder if it is crank seals or running to rich maybe?

And before this thrash check yor gearbox oil.

And after this thrash check it again.

Did you do the gearbox vent bubbles test I mentioned then that is a good indicator of RH seal failure and is easy to do

i cant find the right tube all i can find is the carb overflow