1981 KZ750 LTD four questions
- TexasKZ
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Re: 1981 KZ750 LTD four questions
17 May 2025 18:10
Could the cam bearing surfaces (in the caps and the head) be worn enough to let the cams wobble?
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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- bluejacobs
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Re: 1981 KZ750 LTD four questions
18 May 2025 05:28
I suppose it is a possibility, but earlier in the thread I checked a couple of the cam - cap clearances with plastigauge (on intake 1/2) where I was seeing the largest differences between the two valve clearance methods and they were both in spec... frustrating. Guess I'm going to keep playing with shims and reassembling until it all drops into place.
1981 Kawasaki KZ750 LTD - crashed 4/24, rebuilt and rode the rest of the year; undergoing DD/TLC
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
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Re: 1981 KZ750 LTD four questions
18 May 2025 06:04
Oops, sorry. I should have reviewed before posting.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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- TexasKZ
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Re: 1981 KZ750 LTD four questions
18 May 2025 06:38
WARNING! Wild speculation coming your way.
When you measured the cam journal clearance, did you measure between the cap and cam journal, or between the journal and the head? Assuming the head was fully assembled, it seems to me that since the valve springs would be pushing the cams away from the head, the gap under the cam journal would increase as the cap wears.
Soooo, if any of this is true, and you measured the cap side as the cams were in the upward portion of their wobble, you could have gotten misleading measurements.
I suppose a couple of sticky valves could account for the inconsistent measurements, but that seems to me unlikely since you have been riding the machine.
I am afraid this is all my two cents will buy for you.
When you measured the cam journal clearance, did you measure between the cap and cam journal, or between the journal and the head? Assuming the head was fully assembled, it seems to me that since the valve springs would be pushing the cams away from the head, the gap under the cam journal would increase as the cap wears.
Soooo, if any of this is true, and you measured the cap side as the cams were in the upward portion of their wobble, you could have gotten misleading measurements.
I suppose a couple of sticky valves could account for the inconsistent measurements, but that seems to me unlikely since you have been riding the machine.
I am afraid this is all my two cents will buy for you.
1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
www.kzrider.com/11-projects/620336-anoth...uild-thread?start=24
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- bluejacobs
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Re: 1981 KZ750 LTD four questions
18 May 2025 14:23
I was measuring topside between the cap and cam, but I do see your point. I swapped two more shims this morning, buttoned everything back up and ran through the FSM measurements and everything is in a range that I feel good about, (0.15mm or better clearance) EXCEPT ONE.
Does anyone happen to have a 255 shim (92025-1101) laying around they can spare? I made a Wanted thread, but figured I'd post it on the host thread as well just in case, before I go shelling out the one size I don't have more than one of...
Does anyone happen to have a 255 shim (92025-1101) laying around they can spare? I made a Wanted thread, but figured I'd post it on the host thread as well just in case, before I go shelling out the one size I don't have more than one of...
1981 Kawasaki KZ750 LTD - crashed 4/24, rebuilt and rode the rest of the year; undergoing DD/TLC
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
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- bluejacobs
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Re: 1981 KZ750 LTD four questions
09 Jun 2025 10:47
Ordered a 255 shim and got it put in, rechecked clearances and they were finally all nice and happy! Reassembled after cleaning up the old cam end plugs and letting them cure in place, did a skim of oil on the head facing side of the gasket, and just a little black RTV over the tops of the cam end plugs about 1/4" onto the aluminum. Torqued everything down and let it all set up for 24h, and jumped right to life when I went to start it up. Ran great for 2 minutes on full choke and then randomly surged and stayed at 4k RPM, went to 5k when I opened the choke a bit so I shut her down. Came back about 20 minutes later, tried again, same deal for about 20 seconds then returned to a normal, even idle... Odd.... at least to me. Warmed it up well and took it for a few miles and everything felt great so not sure what the issue was. I did check all my rubber bits and the valve cover and didn't detect any leaks so I'm kind of stumped, but its running again, just in time for my new bike to show up (hopefully today)!
1981 Kawasaki KZ750 LTD - crashed 4/24, rebuilt and rode the rest of the year; undergoing DD/TLC
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
1981 KZ440 A - was running until the end of 2022, sitting in a barn for now
1981 KZ440A - donor bike
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