Well gentleman I have found et another problem with my 99 EVO. The other night I was working on an oil change for her and after firing her up I noticed a blueish gray smoke from the rear cylinder. The front has it some but not near as much as the rear. The only way I noticed this was because I had a work light set up near the exhaust. When I started her up I noticed she had no smoke but after a few seconds it had a very faint "smoking". I checked to make sure I wasnt overfilled. Nope. Checked to make sure the air filter wasn't soaked. Nope. So I ran a compression test. 165psi both cylinders at operating temp. So rings should be good. The bike has only 17k miles but the previous owner let it sit for a few years in storage. Best thing I can think of is valve seals. I do not have he proper tools for a leak down test. But upon further inspection the smoke looks gray and smells like gas. The smoke doesn't linger like burnt oil. It burns my eyes like fuel. The smoke seems more prevalent on decel but yet again you have to have a light on it to see it or it must be really sunshiny outside. Valve guides or valve seals or both? should I just run it and see if the valve seals were just dry? The plugs seem ok. Front is nice and tan and the rear seems to have a small amount of carbon like it has been running rich. No wet oily plugs. Any help appreciated! Thanks all.

 

I'm going with fuel. Blueish gray burns eyes like fuel more prevalent on decel. Rear plug looks like it's a small amount of carbon.
If you have no spark and you crank the bike it will smoke like that. From the fuel

 

Left is front right is rear. Rear is the one with a heavy smoke pattern. These plugs have about 3k on them.

 

you could have a stock tin seal that is loose on the valve guide seen it many times

ride it for the season and do a jan / feb top end heads off and replace them, with the up dated blue rubber seals

 

Ok lets try this without the glut of information.
The bike sat for a long time and now it is smoking right?
Plugs and compression are good right?

Hell with it run it and see if it goes away.
Maybe a little marvel mystery oil will help.
Save the tear down for when you need to.

 

I've seen that kind of smoke or vapor many times, at night with car headlights for example.. Mine does it and the rear more than the front...
How much oil do you burn between oil changes?
Those plugs do not show an oil usage problem to me..
When you are running the bike, is it at normal operating temperature with the enricher off? You will see that kind of smoke when they are running rich.


Ride it....


Ds

 

Sounds like valve seals. Very prevalent on decel. Plugs make it look hardly noticeable. Keep riding till it's more obvious and wait till winter..........

 

What did you put in for oil and is that the norm ??

 

im with texashillcountry here , put some miles on it and enjoy .
Ckeck the plugs after some decent usage and decide then if you have a big problem.

 

In agreement with the others, ride it, and don`t give it a second thought until you see that the engine is using oil.