Valve damage

[Speeddog]

Looks like a fairly standard burned valve.
I'll run the pic past my cylinder head gurus.

Got a pic of the top of the piston?
I'm surprised the piston survived longer than the valve.

Does it still have opener clearance?

[stopintime]

No piston picture. It's mostly black - if not all black. I remember seeing a patch of bare metal through the plug hole, but can't remember noticing it when I lifted the head. None of us noticed anything unusual...

Opener and closer clearance 'within spec' (didn't write it down)

[stopintime]

Piston: can't see any damage. The soot(?)/carbon build up just under the valves were flaking off - peeled off easily.

[Speeddog]

The exhaust valve sheds heat through it's contact with the seat, and through the stem into the guide.
Anything that compromises the contact of the valve to the seat, prevents that area of the valve shedding heat to the seat.

The laundry list:

Debris; carbon, dirt, etc.
Valve slightly out of round.
A scratch on the valve face.
Valve slightly bent.
If the seat was replaced, and not quite pressed all the way in, it can move and thus compromise the contact.

My head guru commented that there's a lot of carbon buildup for such low mileage after rebuild.
   

[stopintime]

Thanks for helping 

The rebuild was a warranty/scam job for cases and I can't confirm that the heads/pistons were cleaned. Valves were changed and guides were confirmed ok. Trust is at an all time low, so I don't know what to believe...

I'll deal with them however I can, but I'm not going public with any of it. Yet. PM me if curious.

[stopintime]

Valve replaced, seat freshened and runs well - we just started it and listened for odd noises - I will test ride tomorrow and take it from there.

/  / 

[koko64]

Glad that worked. Still running ok?

[stopintime]

Glad that worked. Still running ok?

Yes 

Fingers crossed and all that