Valve guides interchangeable?

[MrKaizer]

Hi folks,

I noticed that some online shops / manufacturers use the same part number for valve guides for GS1000 and Z900 (for example APE VK900). Additionally, in said APE kit, all the guides look the same (no difference between intake and exhaust).

This leads me to assume two things:

1. I can use Z1/900/1000 valve guides (OEM or aftermarket) in my GS1000.
2. I can use OEM intake guides on the exhaust side, even though they have a slightly different shape.

Is this correct?

My reason for asking: Exhaust valve guides seem to be hard to get in Germany. But I still have two for the intake side and there is a shop that sells guides for the Z1.

[Gixer1460]

As APE is an aftermarket seller of 'mainly' race orientated pieces it would be reasonable to assume any 'similar' part may need honing for fit and maybe adjustment in the valve seal area - but saying that if the outer and inner bores suit the head & valves I can't imagine any reason not to use (usual caveats apply) The GS was just a slightly less complicated variation of the Zed motor after all!

[MrKaizer]

I just wasn't sure how important the lenght of the guide is. As in, how far it protrudes into the airstream. Because this probably has some impact on how much it can cool the valve. But if they are doing it for racing it can't be that bad.

And yeah, the "racing spec" is a bit of a problem, having to ream/hone the guides. I'd be happy with using OEM stuff, but like I said, that seems hard to find in my neck of the woods. I'll just have to see how far I'll get.

I didn't realize the GS and Z motors were that similar.

[Toecutter]

Z and gs share the same guide sizes. If you need any, fastec racing in UK have what you need. 

Cheers,

T.

[Reinhoud]

Pretty sure the GS1000 has shorter guides for the exhaust side.

The local reconditioning company swapped mine over, ex in in, and vice versa

[MrKaizer]

The OEM ones are, the aftermarket ones seem to be the same length for in and ex.

Do you mean they swapped them on accident or on purpose? If the latter, did they state a reason? Did you notice any difference?

[Reinhoud]

I asume by accident.

The head is gasflowed, it has a better throttle response, bit more agressive over a ported one.

Never had it installed before I had the guides done, so I couldn't tell you

[MrKaizer]

It's been a while, but I should finish the story.

In the end I bought a full set of OEM Z1000 guides. They were the same dimensions as the GS1000G's but the groove for the circlip is slightly further up. This means the guide is protruding further into the port. This was no problem on the inlet side but on the outlet I had to "fettle" the valve stems a bit to make them go all the way in. And there is only the smallest gap between the valve stem seal and the lower valve spring seat, so removing the seals is going to be a b*tch. But that is a problem for future me (he hates me)