Recutting valve seats

[clinto]

This is what I'm working with.Has cleaned up a fair bit but I need to recut 6 of the valve faces.
Has anyone had experiance with useing amazon-ebay cutters?Those Yankee carbide cutters look the bis but very expesive  for 6 cuts.

[clinto]

sorry folks,cannot upload pics with flickr

[Bryanj]

Honda valve seats are not suposed to be cut but ground with special kit.
Valves should never be refaced but only replaced

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[imghttp://20251130_125752 by john clinton, on Flickr][/img]

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Got there at last,The seats are pitted a bit and grinding  does not clear them.requires a recut of the 3 angles

[taysidedragon]

That head looks in a right state. You might be chasing a lost cause trying to clean that up.
An expert machinist may think differently but I think you may be better off trying to get a different head.

[Oddjob]

Tbh that head looks a bit junk so why not try and see if you can do it. I’ve used the genuine Honda tool for seat recutting. It’s air driven and uses stones not metal cutters. The original tools for the 500/550 were however metal and hand operated, try and look for something similar and have a go.

[Grewth]

I've got a couple of heads in a similar state.
Plus one that some idiot shot blasted with the valves and springs in place.
I'll be watching this with some interest.
Hopefully you'll be able to save it.
You're not charging yourself for your time, so an alternative approach might save the day, even if it's not economically viable in a commercial repair shop.

[Bryanj]

Those valves are not safe to use in my opinion, when i said grinding i meant what oddjob said as in shaped grinding stones not grinding paste and a stick.

To even touch the seats on that head would need a Newway cutter set and sit down before you check the price of a kit, i have one bought at auction, no i wont lend it out, reaso is they have tungsten carbide tips not hss and just for info an ebay advert for a set

[AshimotoK0]

Wasn't there a Honda kit that was loaned around dealers to recut valves of certain type that were not Stellite ( or similar) faced but solid   Trigger had one
 (I  think Julie sold in on here). Graham (Trigger) reconditioned my CB750K0 cylinder head (new guides from Yamiya which I think he told me are the biz).  I deffo didn't get new valves though.

 My CB750 and CB92 Genuine Workshop Tool kit both have 3-angle hand cutters set in them ... so I would guess that's what Honda dealers were intended to use those in the first instance to recut the valve seats.

Berni Saunders ( Honda restoration guy) always talks about a Serdi machine or something ... I guess Bryan/Graham/Ken will know about that.

I got some bargain Neway cutters from a member here and they do look good quality as Bryan says. Think it was from a member who used it once and was emigrating .... Bryan will know who he is.

[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]

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

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.