Worn valve seats

[complete zedness]

A few years back I was having trouble getting valve clearances, the exhaust valve seats were badly worn, I am guessing that running straight through pipes didn't help here (see previous post) There is only so far you can go grinding shims and tipping valves so I decided to bite the bullet and spend some beer tokens on sorting out the problem.
There are two ways to go from here, either a replacement head - now I'm not 100% sure on this and stand to be corrected..... but I believe that the heads and cam bearing caps are line bored, no mix 'n match here then. Based on this I am of the opinion that unless you can find a head complete with the cam caps don't bother.
Alternatively........ get the valve seats replaced.
There is a wizard of a motor engineer over in Thornton on the Fylde coast who I have used in the past. He's an old school guy and just walking into his workshop is a humbling experience full of lathes, milling machines, surface grinders, boring machines and all sorts of other good stuff. He made and fitted 8 new seats, fitted new valve guides and honed the barrels. For this work he relieved me of £380, a fair price when you consider that it keeps the engine authentic and you basically have a new head to go at. Now back on 3.00+ shims all round.






That was winter 2009, since then the bike has done around 3000 miles with no issues to report other than changing a couple of shims as things bed in.

Contact details for anyone interested

Dave Burton Engineering
Thornton
FY5 4HH
01253 868111

[Z.O.A]

You are correct, the caps and head were done that way, however if you know what you are doing you can use cam caps from one head on a different one, it's precision work with very close tolerances but can be done no problem once care and time is taken.
Anyone who scraps a Z head just for that would be mad.

[jimmock]

I think what you've done is the ONLY way forward.

I have the same problem on one of my heads and decided many years ago that the new seats route was the way forward.

Jimmock.

[Pigford]

+ 1 with Jimmock

Looks like the usual cracking at the sparkplug hole on #2

[complete zedness]

Eagle eyes there Pigford, same problem on number 3 as well, as things stand they are not cracked all the way up so compression is still good. Any ideas on a fix for this when they eventually go?

[GEZ635]

The cracks should have been repaired when the seats were changed. Dont wory about it, they have probably been cracked for years and will probably last for years to come. Just ride it and enjoy it.