No, I meant that most of the yamaha's I ride with burn oil. Yamaha does make a decent bike, but I'm a honda fan all the way.[img]i/expressions/face-icon-small-wink.gif[/img] Is your oil clean and fresh? Cat500i may be right about you needing new rings. How many miles or hours on your engine? Have you done any mods like pipe, k&n or jet kit? What's your spark plug look like?

 

Hey, ttom, I have heard of people getting water into the oil and it getting into the oil cooler. This caused the same problem you're having, and just changing the oil won't fix it completly. If water is in it you need to remove it and flush it out in order to get rid of all the water. Let us know how it turns out.

 

As the rancher is air cooled if it is water you got it from an external source. Do the oil flush as Angry suggested, but if that dont work I would think at least you have a colapsed ring on the piston. Your best case then would be just a honing and re-ringing. That will depend on the look of your cylinder. Let us know how this turns out..
My 440ex started to smoke a bit a while back and it got to the point I could not run synthetic oil as it would smoke constantly. I went to a non synthetic oil and it does very little to no smoking. but I do use a small amount of oil. I tore it down last weekend and found that my rings where wore. and I have a few minor scratches in the cylinder sleeve that would not completely come out with honing. I either have to re-sleeve it or put new rings on and put it back together and ride it for a while longer until I get about $500 to have the new sleeve put in and a new piston kit...

 

On a side note, the service manual says to never use synthetic oil, or any oil with energy conserving wrote on the label on bottle. It makes the clutch wear much worse, and in turn contaminates your oil faster. I don't know if there are other reasons or not, and it may not apply to the 400ex, because i think the oil for engine and clutch may be seperate on it? Ttom, you never said if you got water in it or not, but being from kaplan, my bet is you did. Did you get it fixed yet? I used to work for slemco in lafayette and there was a guy there from kaplan. I think his name was adam solieu.

 

If it is really white smoke, or more white than blue, it means you have lower compression due to a seized piston or scored cylinder allowing lots of oil to go by the rings, to the point where it doesn't burn it all in each cycle. You need to do a top end rebuild before you blow up your piston and end up tearing the whole engine apart.

 

hey if it is smoking white there is an easy fix buy a bottle of iso heet it cost about 99 cents and its a gas additive