Topic: Decking Gone Bad... Scoring in Cylinder Head Surface

[KV41]

SOHC,

 I am building a bike for a client and I came across this issue. My instinct is telling me I need to buy a new head however I sent this off to a machinist without noticing the terrible decking job gone wrong from the previous owner. Typically I’ll pull a head off a “good running” bike and its in good condition I know it’s going to be reworked so I’ll send it off. This one slipped by. It either moved while under cut or the dude had no idea what he was doing and threw it back on the bike unfortunately for me to find it now. It has a brand new valve job but I am sketched out by the scoring and don’t want issues sealing. What are your thoughts?

[Tracksnblades1]

41,

Can you tell if a competent .010 to .020 cut will clean it up......
If selective head gaskets are available you could set your quench at the same time....

[754]

It's probably about 10 thou, you can work it off by hand maybe, takes a while.
 I know exactly what causes that. .

[KV41]

745,

If I work it off by hand will I still have to get a larger base gasket?

Tracksnblades,

Thanks I’ve been looking into it.

[754]

At 10 thou probably not,  but you can probably get a thicker gasket.
 Head cutting the  cutting spindle has a very slight tilt, like a thou or two across a 12 inch  circle. When  spindle  is set up dead flat it sometimes picks up a metal shaving under the cutter, that is how the marks get there. 

[dave500]

does your finger nail catch on them heavily?probably might not even matter?

[ozpacman]

What about some carefully applied Devcon/JBWeld type product? I couldn't see why it wouldn't work.

[MRieck]

 Some of those cuts go right through the fire ring area which isn't good. For 50.00 or so I'd have a competent shop mill it. Like Frank said .010" should clean it up. Could also have some areas tigged/milled just to make sure the fire ring will seal.

[scottly]

SOHC,

 I am building a bike for a client and I came across this issue. My instinct is telling me I need to buy a new head however I sent this off to a machinist without noticing the terrible decking job gone wrong from the previous owner. What are your thoughts?

I think you didn't notice the terrible decking job because it wasn't there before the "machinist" got his furry knuckles on it?? The surface has been sanded, and if the motor had been run with those gouges, they wouldn't be clean. As far as cleaning up the surface, how much has already been removed??