1977 KZ1000 Head-What's a good mileage to Repair?

As a general rule, how many miles can you get out of a KZ1000 head before it needs a valve job? I do believe that they had better guides than the 900's. Is a head with 25,000 to 30,000 miles still good to go for a while?

If the valves have been shimmed properly on a regular basis over the years, police departments get 75-80k out of the top ends.The problem are your valve stem seals. They get hard and start leaking with such a long exposure to heat and oil.

Thanks otakar. Wow, so probably double the mileage that you'd get from a Z1 head? I just picked up another KZ900 project with 52,000 miles, head needs a thorough going over. I may just grab a used 1000 head for now and run it. Put new seals in of course.

with 52k on it, I would be looking real close at the rings pistons and cyls, since you are taking the head off not that much more to do the full top end and you prob wold want to include the timing chain guides as well, they get hard and can cause problems down the road

Yeah, the whole top end is off, and the timing chain stuff is indeed disentegrating. I am going to check the bores tonight. I figure that they'll be out of spec, I just wonder if they're too far gone to re-ring. My other KZ900 project was right at the spec limit of cylinder bore with 23,000 miles.

I didn't want this bike to take away resources from the first project, but it's inevitable I guess!

depends entirely on how well its been maintained

Wouldn't suspect any difference in top end longevity among Z1, KZ900 or KZ1000.

How was valve guide on KZ1000 better than Z1 and KZ900?

Good Fortune!

EricHa wrote:

As a general rule, how many miles can you get out of a KZ1000 head before it needs a valve job?

Those were the cop bikes used throughout Kali back in the 80's. The machine shop that did my head also serviced their fleet. They told me the average mileage for a service bike was about 20k miles between head jobs. City riding is worst for a bike. Mine had about 45k at the first valve job, the machinist thought I was bringing it in for it's second valve job and couldn't believe it was the first.

Patton wrote:

Wouldn't suspect any difference in top end longevity among Z1, KZ900 or KZ1000.

How was valve guide on KZ1000 better than Z1 and KZ900?

According to Dave Marsden:
In the original Z1 cylinder head, the eight valves moved in bronze guides that were pressed into the head and secured by small circlips. These guides proved to be too soft for the job and were one of the few mistakes Kawasaki engineers made. They were later modified to a cast iron item.

EricHa wrote:

Patton wrote:

Wouldn't suspect any difference in top end longevity among Z1, KZ900 or KZ1000.

How was valve guide on KZ1000 better than Z1 and KZ900?

According to Dave Marsden:
In the original Z1 cylinder head, the eight valves moved in bronze guides that were pressed into the head and secured by small circlips. These guides proved to be too soft for the job and were one of the few mistakes Kawasaki engineers made. They were later modified to a cast iron item.

Yes, but from the info as presented by Mr. Marsden, am thinking the change from brass to iron was done during the 1973 Z1 model run (no clue as to engine number), so later '73 Z1~'76KZ900 would have the iron guides. "Were later modified" is mentioned in the '73Z1 engine chapter, without further reference in later chapters on '74Z1~'76KZ900 or about KZ1000.

Except for early '73Z1 heads with brass guides, am thinking subsequent Z1 and KZ900 heads have the iron valve guides. (But not positive about this.)

Good Fortune!

Interesting ---
kzzone.com/valves.html

HIGH PERFORMANCE BRONZE VALVE GUIDES

APE valve guides are designed to take the abuse of today's modern high horsepower engines. They are made from special bronze alloy to resist wear and heat. No other valve guide that you can buy will out-perform APE guides. Fact is we supply our guides to nearly all of the top cylinder head shops. Major police departments use them in their patrol bikes which see severe use.

APE guides are precision machined with the bores finished to size.
They are designed to fit lower in the head to clear high lift cams, and use APE seals or factory OEM seals. Sold in sets of 16

---

Good Fortune!

Patton wrote:

Interesting ---
kzzone.com/valves.html

HIGH PERFORMANCE BRONZE VALVE GUIDES

APE valve guides are designed to take the abuse of today's modern high horsepower engines. They are made from special bronze alloy to resist wear and heat. No other valve guide that you can buy will out-perform APE guides. Fact is we supply our guides to nearly all of the top cylinder head shops. Major police departments use them in their patrol bikes which see severe use.

APE guides are precision machined with the bores finished to size.
They are designed to fit lower in the head to clear high lift cams, and use APE seals or factory OEM seals. Sold in sets of 16

---

Good Fortune!

wheres Billy Mays when ya need him,,,lol,,and I know hes gone