Smokes only when cold/warming up.

Had work done on the motor,http://www.thumpertalk.com/forum/showthread.php?t=925466&highlight=

It seemed to smoke only after washing it, probably a coincidence. Then it would do it once in a while (cold). Now, every time it's cold. It always stops, and the motor runs great.

Learned that there is a o-ring in the valve guide that should get replaced, but its a little involved to get to, and the mech thought it was OK to leave.

Is that what the smoking is from? Or perhaps I have another issue?

Thanks

What did the mechanic do to the motor..??and yeah there's some other type of seal on the valves than just the top ones but they are fairly bulletproof..

Two valves were replaced I think they were the exhaust, valve job, replaced rings and honed cyl. One main bearing, replaced 2nd to fix ratio gap, and third gear, worn.

Specifically what seals and o-rings? not sure, only that the small o-ring in question was left alone.

Hard to say what's causing it..Maybe I should just say live with it or we could be discussing possibles forever..Might be that a guide was also worn and needed doing..I dunno really ..so many maybes with smoking..I take it that it never smoked before he did the work..

Hard to say what's causing it..Maybe I should just say live with it or we could be discussing possibles forever..Might be that a guide was also worn and needed doing..I dunno really ..so many maybes with smoking..I take it that it never smoked before he did the work..

No, but it has used oil since before he did the work.

Smoke on cold startup that quickly disappears = leaking valve stem seals. Smoke that gets worse as the engine warms up and continues = worn rings/piston/cylinder wall.

What do you call quickly? Mine may smoke for up to a min.

Smoke on cold startup that quickly disappears = leaking valve stem seals. Smoke that gets worse as the engine warms up and continues = worn rings/piston/cylinder wall.

Either one a problem! Don't ask me how I know!

Care to share what happened?

What do you call quickly? Mine may smoke for up to a min.

I have had several XRs that had stem seals leaking, smoke usually clears up in 2 or 3 minutes. Keep an eye on the oil level, if there is no appreciable oil loss, I wouldn't worry about it too much.

Mine used to smoke like a coal burning locomotive when it was cold. What is happening is a small amount of oil is leaking past the valve seal when it sits and has to clear out of the combustion chamber when you fire it up. No real harm except your head is going to get a nasty, greasy carbon build-up on it which will lead to problems with pinging. Been there, done that. Mine never burned enough oil to cause a drop on the stick, but it should would put out a cloud!

My XR500R had the same symptoms and I ran it like that for several years adding oil occasionally, it ran great, no problem really. Eventually the valves got carboned up and it started smoking at all times. Basically once it finally started to truly go bad, it went fast. We just tore the top end apart and it's crusted black burnt oil... valves, chamber, exhaust port, even the intake port (no idea how the oil was getting into the intake ports). Otherwise it has normal wear for 27 years, can't wait to get the cylinder/head done and other parts so we can build it and break it in. :smirk:

I have the exact same problem, it will only smoke when cold and not every time but most times it will. It started doing this when I removed the smog crap and piped the base right to the airbox. I am going to re-install the oil separator back on some day. :smirk:

and piped the base right to the airbox. :smirk:

Can you explain this? I want to check if mine is routed the same way. Could have been mis routed after the work was done on my engine.

I removed the smog pump on the side of the engine and removed the black oil separator. I connected the pipe that was connected to the base and connected it to the air box where the oil separator was connected to previously. I am thinking of re-installing the oil separator back.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now