SOHC.co.uk Forums > CB750
Recutting valve seats
Bryanj:
A Serdi is a big industrial machine like a Bridgeport mill that can replace seats and recut the angles acuratly, not a home tool and only big machine shops have them.
I must admit to never seeing hand cutters in the dealers kit, may have been an early one, all the Honda seats are supposed to be Stellite which is why they say grind with stones.
I know Trigger found a full stone kit some years back and was happy to buy it, dont know if he sold it.
Those valves just look too rusty for me to trust them in everyday use, head comming off would totaly trash the motor
AshimotoK0:
--- Quote from: Bryanj on February 10, 2026, 12:06:00 PM ---A Serdi is a big industrial machine like a Bridgeport mill that can replace seats and recut the angles acuratly, not a home tool and only big machine shops have them.
I must admit to never seeing hand cutters in the dealers kit, may have been an early one, all the Honda seats are supposed to be Stellite which is why they say grind with stones.
I know Trigger found a full stone kit some years back and was happy to buy it, dont know if he sold it.
Those valves just look too rusty for me to trust them in everyday use, head comming off would totaly trash the motor
--- End quote ---
I know that 450 Bomber valves are Stellite faced Bryan..... But pretty sure that at least the early 750 valves were solid and Trigger deffo refaced them for me with that full stone kit .. he did sell it to a member on here. My 750 toolkit has a separate little green box inside the main box with the cutter set in it. Still totally unused in my kit as Graham did my head refurb. It came from Alf Briggs's stuff (he was Honda's main service man in Nottingham and a very close friend on Mr Honda himself).
Interesting article on Alf here : https://www.dropbox.com/scl/fi/5l31rcxe39ljobilv6d9k/Alf-Briggs-5.pdf?rlkey=rsg3natiqsqi752zi6w09grp2&st=v48vy2ns&dl=0
I agree that the head looks pretty knackered. I think my 500K0 had Mitsubishi manufactured exhaust valves. (were they Stellited)
Bryanj:
Dont know for certain Ash but i do remember a Honda tech rep telling me no Honda valves should be refaced on grinder only lapped in
Laverda Dave:
I remember having the valve seats re-cut on a Serdi machine by the Cylinder Head Shop when he was based in Wimbledon back in the early 90's. That was on the 400/4 I've just sold. He moved to Ireland not long after but is now back in England although likely retired by now.
clinto:
So far not seen any stone kits for sale and as for the newway cutters,2 plus guide would be in the three hundred pound plus.
Another option is another head but looking at whats on offer some look no better than mine.Some better looking than mine come with the added benifit of damaged /broken fins plus unknown condition.
A trip to the semi local machine shop for their perusal is in order me thinks.
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