valve seat angels 750 s (1970)

P

Peerless

Junior member
Hi

Im going to cut my valveseats and the bloke who has the equipment asked about the angels. Please correct me if Im wrong butIi believe they are 45,30 and 75. 1.5 mm wide on the inlet and 2mm exhaust. Any input is welcome.

David
 
you mean 30/45/75(70) to 90 with the 45 seats 1.5mm (.060") wide for intake and 2mm (.080") wide on Exhaust. Depending on Valve Diameter being bigger diameter will allow the 75 or 70 cut on the intake to be say .070" to .100" wide before hitting the 90. Keep the 75 to 90 edge sharp. Again depending on Valve Head diameter the Exhaust is best cut 30/45/ with a series of narrow width cuts at say 60/70/80 before the 90. The edges of the 60/70/80/90 can be smoothed with a Cylinder Brake hone and blended into the 90 to shape a Venture.

As I say, depending on the Size of the Valve Heads you may not be able to achieve these cuts.

A lot of the members in this forum believe seat widths of int/exh @ .060" /.080" too narrow for an Air Cooled engine where the seats should be at least .070"/.090" respectively. I run the seats on my 750FS at .060"/.080" and have not had issues.

 
Mine have a visit from the fuck-up fairies from time to time...
 
Well, the Neway cutters we used today were like angels making angles. But then i fucked up the exhaust valves in the lathe...

David
 
Nah, c'mon guys, we aren't talking Z*** here, we are discussing the motor that looks like the one in that Godawful styling exercise the 750 SFC.
I mean, who on earth designed an engine with that lump poking out of the front!
What was needed was a pleasing aesthetic view, just like a Thruxton Triumph/Triton thing of beauty, where the neat swept back exhaust pipes enhanced the beauty of the motor, (and I am not going anywhere near the Headlight, "stuck on the front, that'll do" design cock up!).
(Giggle!)
 
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