Michael,
According to my Clymer manual, it calls for 30, 45 and 60 degree cutters for the valve seats.
Here are some of the rules for heads and valves:
5. 1200 CYLINDER HEAD: The original equipment cylinder head of an un-sealed engine must remain in unaltered “as cast” condition with the exception of machining the gasket surface (no angle milling allowed). Valve seat inserts may be reworked or replaced with OEM or aftermarket seats of original dimensions. The stock I.D. at the bottom 1/16 of an inch is 0.990” for the intake port and 0.830” for the exhaust port. No port alterations of the intake or the exhaust below the seat are permitted. Oringing the head gasket seal area is not permitted.
Combustion Chamber -Relief cuts for cc balancing may not exceed the bore size.
Repairing Heads -A combustion chamber may be repaired by welding and grinding back to the official “stock” configuration of the combustion chamber.
14. 1200 VALVES: Only stock Yamaha FJ1200/XJR1200 valves are permitted. No modifications are permitted to the valves with the exception of altering the number of angles of the seat and a maximum back cut width up to 0.200” is permitted from edge of the valve. Valve jobs are permitted. Only stock valve lifter and adjuster shims may be used.
15. VALVE GUIDES: The valve guides must remain the same size, length and location of the current “stock” valve guides. The guides may not be altered in any way. Shot peening of valve guides are not permitted. Brass aftermarket valve guides of the same dimensions of stock may be used.
16. VALVE SPRINGS: The valve springs may be replaced with aftermarket magnetic steel springs. Only stock steel valve spring retainers and clips/keepers are permitted. No titanium or other lightweight alloys are permitted.
I am sure some of the engine guru's can elaborate on what most people are doing to their engines.
Steve
