Kawasaki Z1000 R2 cylinder head

[Pip 64]

IMG_20250314_162340.jpg

Hi to you all, fairly new member here after joining earlier this year.
I bought this none runner in April as my next project which I could do with some advice on cylinder heads due to the camshaft caps bolts have stripped threads and was wondering what other models have the same heads. Pip

[KevH]

If it's just the threads that are an issue they should be easily repairable. There are some good inserts about nowadays and most engineering firms will do them for you. Much better than Helicoils.

[warren3200gt]

Helicoils are fine for that application. You don't need to torque the hell out of them. People using fsm torque settings on 40+ year old stretched bolts and worn aluminium threads is the reason they've stripped.

[zed1015]

The stripped threads should be an easy fix.
You can actually drill the holes deeper if needed and fit 20mm helicoils.

The genuine Kawasaki bolts are around £4 each but you can buy exactly the same spec bolts at 28p each from the link below.
You can pick the length you need ( 50mm if you fit the 20mm helicoils )
https://www.ebay.co.uk/itm/114307030889 ... 4558257426

Here's a pic of the latest head i've done.
With the bolts being longer there is a lot more thread engaged in the head before they start pulling the caps down so no need to clamp the cams as some people do.
They are never going to strip again after this..

cylinder head.JPG (208.21 KiB) Viewed 147 times

cylinder head two.JPG (186.54 KiB) Viewed 144 times

[Z1streetfighter71]

Just out of curiosity could you move up to a M7 tap with a 1mm pitch on all bolts?

[zed1015]

Just out of curiosity could you move up to a M7 tap with a 1mm pitch on all bolts?

M7 tapping drill is 6mm but stripped out m6 threads are most likely to exceed this with the resultant re tapped M7 having less bite than if done in a precise 6mm hole.
M7 bolts are also less common and usually much more expensive so probably more cost effective just to helicoil.
Re tapping a good m6 to m7 is fine but then why bother.

[Z1streetfighter71]

Just out of curiosity could you move up to a M7 tap with a 1mm pitch on all bolts?

M7 tapping drill is 6mm but stripped out m6 threads are most likely to exceed this with the resultant re tapped M7 having less bite than if done in a precise 6mm hole.
M7 bolts are also less common and usually much more expensive so probably more cost effective just to helicoil.
Re tapping a good m6 to m7 is fine but then why bother.

Fair, was thinking there might be a touch of a gain if using M7 for performance cams where the cost of the bolt would be pennies over a bolloxed head.

[zed1015]

Fair, was thinking there might be a touch of a gain if using M7 for performance cams where the cost of the bolt would be pennies over a bolloxed head.

I have previously searched for suitable m7 flange bolts and what little i could find were unsuitable regardless of the stripped hole size issue and the cost far exceeded the combined price of the helicoils and the new M6 bolts i use.
The 20mm long m6 helicoils and 50mm bolts were around 80p per hole so less than £13 to do all the caps.

[Pip 64]

Guys, thanks for all the interesting advice on how to go about resolving this but as luck would have it I managed to obtain a very good 2nd hand R2 cylinder head today that can go straight on once I've lapped the valves in a put new valve seals on as a good measure.
Thanks and let the good times roll again, Pip

[zed1015]

Guys, thanks for all the interesting advice on how to go about resolving this but as luck would have it I managed to obtain a very good 2nd hand R2 cylinder head today that can go straight on once I've lapped the valves in a put new valve seals on as a good measure.
Thanks and let the good times roll again, Pip

Before you re assemble and fit the head you should measure the installed height of the valve stems.
They need to as close to 37mm as possible ( from valve tip to bare head - spring seat removed ), if they are near 38mm you will be running out of shim sizes and may need to tip the valves or take other measures to retain decent valve clearances down the line..