GS1000 valve seats

[Agemax]

Has anyone had valve seats replaced in a GS cylinder head?

A head i am rebuilding has got pitted valve seats on 1 cylinder, there was a lot of corrosion there when i got it so i am guessing the spark plug was left out and the rain or damp has got in.
I may be able to get the faces recut but i fear the pitting may be too deep. The pitting is on all 3 angles of the seat.

Can you even buy new valve seats, or will they need to be made?

 

[zed1015]

Any decent engine reconditioners will be able to replace the seats and they are available in various sizes.
Try SEP at Kegworth .

 

[Agemax]

Any decent engine reconditioners will be able to replace the seats and they are available in various sizes.
Try SEP at Kegworth .

Ok cheers, i am in Plymouth so will try to find somewhere closer to home.

 

[Nessism]

Chances are, a good 3 angle valve job and cleaning up the valves in a centerless grinder will take care of business. Make sure the shop tips the valves to get the shims sizes up in the range. I'm not sure what the proper valve height should be, but some measuring should determine that pretty easily.

 

[Agemax]

Took the head to a local engine tuning specialist and they can reface the valve seats on all angles.
They will also grind the valve stems as required to restore the shim clearance.

I am a lot happier now knowing this, so can crack on and start cleaning up the ports while i wait for new valves to be delivered.

 

[Agemax]

So i had the valve seats recut, now i need to get the tips of the valve stems ground. To get me in the middle of the shim range (2.50 - 2.60) i need to get 0.8mm ground off the tips of the valves. They are not stock valves, they are plasma coated stainless valves.

Does 0.8mm sound excessive? I think it should be ok, even the factory service manual says you can grind off upto 1mm.

 

[Chuck78]

They are not stock valves, they are plasma coated stainless valves.

Where did you get those valves at? Were they intended for the GS heads?

I'm going to guess maybe Nick @ Suzuki Performance Spares?

 

[Agemax]

Where did you get those valves at? Were they intended for the GS heads?

I'm going to guess maybe Nick @ Suzuki Performance Spares?

You are correct, they came from Nick.

 

[Chuck78]

Thank you sir, I think I'll have Rapid Ray fit some of those to a GS425 cylinder head that I've been talking about sending him for a year and a half now. It has 750 / 850 valves in it stock. Big Jay @ APE Race Parts has fit that size of valve into 400 and 425 heads previously with excellent results with some mild porting.

 

[Nessism]

So i had the valve seats recut, now i need to get the tips of the valve stems ground. To get me in the middle of the shim range (2.50 - 2.60) i need to get 0.8mm ground off the tips of the valves. They are not stock valves, they are plasma coated stainless valves.

Does 0.8mm sound excessive? I think it should be ok, even the factory service manual says you can grind off upto 1mm.

.8mm is a LOT. Seems like too much, if you were using stock valves. I'm not sure about those particular valves. One thing to check is if the keepers stick up above the top of the valve when the spring and retainer is installed. I've heard of grinding the keepers in extremely situations.

 

[Agemax]

.8mm is a LOT. Seems like too much, if you were using stock valves. I'm not sure about those particular valves. One thing to check is if the keepers stick up above the top of the valve when the spring and retainer is installed. I've heard of grinding the keepers in extremely situations.

The stainless vaives are exactly the same dimensions as the stock valves. In the FSM it says it is permissable to grind upto 1mm off the tips of the valve. It does sound a lot but even with 0.8mm ground off, the tip of the valve is still above the valve keepers, by 0.2mm. The keepers sit proud of the spring retainer by 0.5mm so i could also grind a small amount off the top of the keepers if needed.