Head job

[b1kawa]

Howdy all, now that I got your attention, after having no
compression in 2 & 3 cyclinders, (1981 GPz1100B1 Fuel injection) I
took the head off and discovered the 2 & 3 ex valves were slightly
open, one valve is slightly bent and were it slides up and down in
the head there is a shaft and that shaft is half broken away. Now
would anyone know could this have caused the valave to bend or if
the valve had bent some other way could the valve have caused the
shaft to brake away?........Next, since I have another complete bike
for spares if I use the head of it do I use the cams/shims etc also
or do I just use the head and use cams etc from my original one
(does that make sense)??????
Anyway since the head is of it will be getting a head job (hence the
heading) by way of porting and polishing........

Phil

[twowheelertoy]

Welcome.
Bent valves can be caused by:
Valve timming out.
Over revving the engine.
The valve guide could of broke up pushing the valve to one side causing it to bend.
Very Very Very badly adjusted valve clearances holding a valve open (But i suspect the motor wouldn't run sharp if this was the case)
I would be looking for witness marks on the Piston crowns to see if any of the valves had contacted.

If you are going to use another head then i would suggest you also use the other components from that head..