Need info on this Performance Yamaha (westcoast made) head & ported 62t cylinder

[Ericfox]

Trying to sell a performance yamaha head and dont know if it fits a 701 or 650... also I have 2 sets of domes for it... any idea on approx compression these could give? hoping someone can recognize the numbers on the head and domes....

Also have a 62t cyl for sale with some porting... I dont know a ton about porting... just that there is freestyle, racing, and different amounts of each.... I dont know if these pics will show much... hope they tell a little at least

Hope to get some info so I can give potential buyers accurate info...

Any help will be much appreciated! Thanks

 

[Ericfox]

anyone?

 

[SUPERTUNE]

If I remember right, the last two diget are the cc of the chamber, so it looks like you have a 701 set and a 650 set.
7030- 30cc
7024- 24cc
These Westcoast heads (made for Yamaha) also use the OEM headgasket, not an o-ring type.

A stock 701 head off of a superjet with a 61X cylinder has 34cc stock, so if you use the 7030 dome your decreasing the combustion chamber by 4 cc's.

 

[Ericfox]

I dont get it... what does ADA use on their numbers? for example: say 35 domes are something like 185psi so does the 35cc mean the estimated combustion cc's on their numbers too?

Why are the 24cc domes from a 650? is it because that much of a change would give too high of a compression number on the 701?

Guessing here because 4cc difference with ADA domes = 30lbs... So those would be good for pump gas at about 185psi...

Anyone on the porting? does it at least look ok?

 

[NJJer]

If I remember right, the last two diget are the cc of the chamber, so it looks like you have a 701 set and a 650 set.
7030- 30cc
7024- 24cc
These Westcoast heads (made for Yamaha) also use the OEM headgasket, not an o-ring type.

A stock 701 head off of a superjet with a 61X cylinder has 34cc stock, so if you use the 7030 dome your decreasing the combustion chamber by 4 cc's.

I have the same head and can add nothing except see above. The man said it all.

If you want to sell those 30cc domes, let me know as I need a set. I already have 26 and 28.

Thanks

 

[SUPERTUNE]

I dont get it... what does ADA use on their numbers? for example: say 35 domes are something like 185psi so does the 35cc mean the estimated combustion cc's on their numbers too?

Why are the 24cc domes from a 650? is it because that much of a change would give too high of a compression number on the 701?

Guessing here because 4cc difference with ADA domes = 30lbs... So those would be good for pump gas at about 185psi...

Anyone on the porting? does it at least look ok?

Think...
.......
.......

O.K.
Now that you just got done thinking.
The piece of the puzzle that your forgetting is the .052 thick stock headgasket. This gasket when used on heads that don't have just o-rings, will displace about 6cc.
A stock 701 head @ 34cc + 6cc gasket = 40cc total that the engine see's as compression volume.
Your Westcoast head @ 30cc + 6cc = 36cc total....
ADA o-ring head with 35cc domes + 0cc (no headgasket) = 35cc's total head volume.

Make sense now?
Chuck.

 

[Ericfox]

oh yeah.... duh.... thanks man