Head filing

[peterg]

Does the filing at the intake valve indicate work done after market?

 

[Jim]

Nope. That's from Yamaha. All XS650 heads have that to varying degrees.

 

[Jim]

Shot of a random head destined for my mockup motor...

 

[peterg]

Thanks Jim. Just another adjustment as the years went by instead of updating the mould?

 

[Jim]

Most likely...

 

[fredintoon]

Thanks Jim. Just another adjustment as the years went by instead of updating the mould?

Yup,
the most blatant example of mold-retention is the left exhaust valve's 4-bolt cover; kept after the exhaust valve lifter removal until end of production.