SOLD - Shim under bucket, GPZ type Titanium retainers to sell or swap.

[zed1015]

Set of new under bucket type (takes 13mm shim) Titanium valve spring retainers for Z650,GPZ1100 etc or to convert your 900/1000.
Prefer to swap for Z9/1000 type shim on top Ti retainers or maybe a set of APE bronze guides or sell £110 posted and I can go buy the ones I need.

retainers.jpg

[rickm]

Is it possible/easy to convert a shim over bucket to under bucket type head? (or vice-versa)

[zed1015]

Yes! Just swap the retainers, shims and buckets.
Don't need to change valves, collets or anything else.

[rickm]

Crikey, that's worth remembering. Thought it would involve major work on the head as I'd not heard of folk doing this before.
Good luck with the sale.

[ADRIAN H]

Crikey, that's worth remembering. Thought it would involve major work on the head as I'd not heard of folk doing this before.
Good luck with the sale.

My Z1000A2 has under bucket shims with a Z1000J head - just to cause more confusion.

[rickm]

So in theory, you could convert it without even taking the head off ? (or even only do some and not all of the valves!)

Apols, not wishing to threadjack.

[Julian_Boolean]

So in theory, you could convert it without even taking the head off ? (or even only do some and not all of the valves!)

Apols, not wishing to threadjack.

Yes, but you'll have to take the cams out.
You'll also have to take the cams out to change a shim, which is a right ball ache, why do you want to go to shim under bucket?

[rickm]

Yes, but you'll have to take the cams out.
You'll also have to take the cams out to change a shim, which is a right ball ache, why do you want to go to shim under bucket?

I don't intend to at the moment, I was more just surprised that it would be so easy to do. I will need to do something with my valves soon though as a lot of my clearances are on the smallest shims at the moment. I know it's possible to take a small portion off the top of the valve stem. Would going "shim under" affect the clearance, and if so then which way (larger or smaller) on the shim sizes?

[Julian_Boolean]

In theory the clearances would be the same, just had a thought though, on Unitrak 1100 engines (which are shim under bucket) the shim sits in a recess on the valve spring retainer, you might have to change the valve spring retainers, which would be a head off job, but taking the head off is not much more work once you've taken the cams out.

The reason Kawasaki went shim under bucket was because the shims could skip out at high rpm.

[zed1015]

So in theory, you could convert it without even taking the head off ? (or even only do some and not all of the valves!)
Apols, not wishing to threadjack.

You really have to do the swap with the head off but it can be done with the head on, you just have to prevent the valve dropping into the cylinder.
It can be done with compressed air or rope stuffed down the plug hole with the piston at tdc to keep the valves seated while you release the springs.
You really need to know what you are doing though.
Swapping to under bucket won't solve valve clearance issues and tipping the valves is the same on both types.
If you are on the thinnest shim sizes with shim over you can tip the valves but also skim up to 1mm off the collets and retainers to get you back in the upper shim range.
You won't find that in any manual though ...
The main reason for shim under is to prevent shim spitting when using high lift cams but the set up is also lighter too.
On the Unitracks etc the change to shim under wasn't really needed as the cams are not that high a lift to cause a problem and was done more for marketing purposes and simply used parts from the Z650 which already had them.
The cause of shim spitting on the shim over is down to the groove that runs round the inside top of the buckets that's there to ease shim removal..
The wider sweep of a high lift cam allows the edge of the shim to rock in the groove and get flicked out like tiddly winks.
The racers fix before shim under was to fill the groove with silver solder or the like which prevented this.
You could also buy performance buckets from Russ Collins etc without the groove.

[buzzard]

Morning Rob, I'll take them if still for sale. Buzzard@thebuzzworkz

[zed1015]

Morning Rob, I'll take them if still for sale. Buzzard@thebuzzworkz

You got them mate.
I'll PM you.

[zed1015]

NOW SOLD.
Thanks.