TOPIC:

Timely subject, since I am debating when to install them. 
Can't decide whether to do it before the valves are serviced, or wait until after I get it back?

I can appreciate that Timeserts are the best, but what does a steel insert do to heat dissipation with an aluminum head?  I think there are aluminum Timeserts, but most people don't bother.

Being the plugs are steel and the inserts are steel it would be better to have them in as they won't wear out like a bare head would. It would be an upgrade. 
Steve

I think heat will dissipate effectively through steel and also aluminum but steel doesn't expand as much as aluminum, and that might be a problem.

SWest wrote:

Being the plugs are steel and the inserts are steel it would be better to have them in as they won't wear out like a bare head would. It would be an upgrade. 

Steve

 

Plus these 44111 inserts have a copper plating.  That probably helps with threading the spark plugs in/out, and provides some level of corrosion resistance.
Installed four while the head was bolted on the motor in May 2022, and had no issues relative to heat dissipation since then that I am aware of. 
I chose steel over aluminum for durability, and not having to be concerned about threads stripping out again.




 

Jut to open another thought train, the clue is in the thread title. Fitting inserts is a "repair" and as such "if it ain't broke don't fix it" If the threads are currently in good shape why not simply install the plugs with a little "anti-seize" and call it done. There are tens of thousands of alloy headed vehicles with six figure mileages out there that have never needed repairing if maintained correctly (IMHO)  would you have a hip replacement for your 60th birthday if you didn't need it ?

The valve seats are cast in, the barrels have steel sleeves as well as everything else that is prone to wear so why not the spark plug threads? One of the things I thought the Z1/KZ1000's had was the shell bearings for the cams unlike the Honda 750's and other bikes like my old 350. It had two bearing blocks the cam rode in. Had to replace them too many times.  I was disappointed to see KHI didn't have them in their smaller fours. 
Having steel inserts only makes sense for high use areas. 
The big fours are totally rebuildable and can last forever. Maybe that's why they did it and not for the newer ones. 
Planned obsolescence? 
Steve

I guess a lot comes down to personal choice and what makes you comfortable. Ref cam bearings - many cars have the cams running directly in the alloy head and with oil changes between 10k and 20k miles (dependent on manufacturer and extended service schedules) comfortably cover 200k miles plus without issue (VW cams ran in the head back when our KZ's were new) I do appreciate that our bikes produce significantly more HP per litre than their 4 wheeled counterparts.

All the trashed heads due to oiling issues. VW's had that problem and the early Honda 750's with their jet oiling system for the cam. The 350 four was the worst one yet. Glad I bought my Z1. Kept it on the road 48 years and still going strong. 
Steve

Wookie58 wrote:

Jut to open another thought train, the clue is in the thread title. Fitting inserts is a "repair" and as such "if it ain't broke don't fix it" If the threads are currently in good shape why not simply install the plugs with a little "anti-seize" and call it done. There are tens of thousands of alloy headed vehicles with six figure mileages out there that have never needed repairing if maintained correctly (IMHO)  would you have a hip replacement for your 60th birthday if you didn't need it ?

 

I had to do something about that loose #3 plug before it could blow out and get welded to the gas tank...so one thing led to another.


 
 

I have used Timeserts on those 6mm bolt however I did not have a milling machine as he does. My pins were a better fit however. Using the pin as a guide I was able to drill it out by hand using the timesert drill. The drill is a very close fit with the pin if I remember so you get a very straight hole. Tapping to was also not an issue. I have repaired a lot of holes with Timeserts and they work well.