VALVES..Lap or Regrind

[gordon62]

Hi all,
I have stripped the engine on my Z1000, and stripped the head, the valve have all been cleaned up, and checked, the ex seem pretty good as in smooth etc, the inlets have very small step? I am wondering if lapping is enough to re-flat the valve seats or should I get them reground..here"s a couple pics,

[Al]

Andy if you can find someone to do it, get the 'throat' and 'relief' angles cut on the valves only.
15 and 60 degrees until the seat contact area is within spec (0.8 to 1.2 mm wide from memory for J models)
Colour the seat contact area with a permanent marker pen and lap them the least amount you can get away with.

AL

[buzzard]

I have a valve refacing machine if your valves need a reface, I also have the 3 angles of valve seat cutters if your cylinder head needs the seats re-cut, but before doing anything I would check the valve guides for any play and also I'd check the valve stem diameters for any possible wear, there's no point in wasting time on valves and seats if the guides and stems are worn. Buzzard.

[gordon62]

I have a valve refacing machine if your valves need a reface, I also have the 3 angles of valve seat cutters if your cylinder head needs the seats re-cut, but before doing anything I would check the valve guides for any play and also I'd check the valve stem diameters for any possible wear, there's no point in wasting time on valves and seats if the guides and stems are worn. Buzzard.

Hi Buzzard,
have sent PM

[jimmock]

I WOULD BE VERY CAREFUL RESURFACING VALVES AND SEATS.

If too much is taken off, the valve recedes into the head too much.

Valve clearances will be too tight and shims of the SMALLER thickness needed are not available.

Valve STEMS then need to be cut back to increase the clearance to the spec that the shims are used for.

BEWARE!!!!

[chrisu]

You may be right Jim but Dave does know what he is doing!