Valve lapping

[Tat2demon]

At what point should you consider valve lapping? My 11 has 25k miles on it and smokes a little on start up so I have been thinking about replacing the valve seals. Should I look into lapping the valves at the same time?

Or should I even bother with valve seals at all if there is no other reason to take the head off?

[TopCatGr58]

If you were truly going to be taking the head off to replace the seals, then YES, I would go ahead and do the lapping. But if you only have a little smoking at startup, but clears once it's running, then like you said, do you really want to tear into it for just a few drops of oil with every cold start!?

T.C.

[Geezer]

The smoking is from the leaking valve guide seals. Since you have to take the valves out anyway to fix this, one at a time inspect them to see of the contact ring is solid all the way round. If there's a spot that looks broken, then there's a leak there and it would need to be lapped in.

If there were one leaker, I'd lap them all but otherwise on a 25k engine, you're grinding away material that would be better off left there until this work really needs to be done.

Make sure each valve goes back in the hole it came out of and be sure to wire brush off all the carbon on the under sides of the valves. You can leave most of the carbon on top of the valve head because it's beneficial (mostly on exhaust valves.)

Geezer

[petejw]

if u decide to take the head off
sit it on its side and fill the ports with fuel
youll see quick enough if the valves are leaking/seeping.

[donebysunday]

At what point should you consider valve lapping? My 11 has 25k miles on it and smokes a little on start up so I have been thinking about replacing the valve seals. Should I look into lapping the valves at the same time?

Or should I even bother with valve seals at all if there is no other reason to take the head off?

What's your compression ?
How are the plugs reading, oil fouled or not ?
A little oil on start up may annoy you with the smoke but if it's not so bad or so long it's lubricating the rings.

[Tat2demon]

Everything else is fine. Just the little bit when it starts. I think Ill skip it for now. Sounds like a good winter project.

[Geezer]

If that's the case, I'd put it off for a couple 3 winters...

BTW, take it out and run the piss out of it from time to time to burn the oil off the back side of the intake valves. It's fun and good for the bike.

Geezer

[Tat2demon]

You mean there's other ways to run it?

[MaximPhil]

You mean there's other ways to run it?

If you ride it like that often I bet the smoke problem clears up a lot.
Phil