Head questions

[Waternut]

I'm trying to figure out what is up with my westcoast head... The head itself is for a 701 but it's got 6528 domes in it. It doesn't really look like an o-ring head but it's got small gaps between the domes and the head which I just figured was normal. Based on the markings, the domes appear to be 28cc 650 domes. When I got this ski, it produced roughly 170 psi. I find it really hard to believe that 28cc domes meant for a 650 would produce 170psi on a 701. Do Westcoast heads have a special gasket that's much thinner than OEM?

Can an o-ring head really be installed with an OEM gasket?

 

[Waternut]

Anyone?

 

[sflsurfrider]

i know that some wc heads use a gasket and o-rings. ive never seen any though.

 

[SQUARE JOEL!!!]

6528's are rated 195 PSI

Not real sure about thickness difference from OEM.

 

[kevbo]

Westcoast used the same head shell for both the 650 and 701. Yamaha domes will not have a step for an O-ring. They fit flush with the shell and use a stock 61x gasket. Kawasaki domes have a step for an O-ring and will fit in the Yamaha shell. These heads MUST use a 61X gasket, a 62t gasket will work if the water holes are drilled to match. Stock head gaskets are best for corrosion resistence. A 7028 dome should make over 180 psi on a stock 81mm 61x cylinder with the squish about .070"