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KZ900 Engine Compression Concerns?
- 2KZLTDs
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Trying to get a 76 KZ900B LTD back on road. Got from brother in law who passed and I don't know the history except it was his bike and he was prior Kaw dealer. Should be good but has sat at least 10 years inside storage. Cosmetically very good and put some small amount of penetrating oil and minor amount of 20-50W in each cylinder and turns over fine. Has less than 13M miles and engine seems stock but getting a range of 85 to 115 PSIG compression test whith open throttle. A can see a lot of carbon on piston tops with plugs out. Also getting 11.5V at the coils which seems pretty good as have read a lot about problems with old wiring needing a new rely and wire to coils. Does this compression and voltage seem a concern? Do you see any issues with now changing oil and trying to start or do you recommend pulling value cover doing shims or even head, or something else before this step ?
1976 KZ900B LTD (One runs, One rebuilding)
1980 KZ1300B (Next rebuild/may sell)
1983 KZ1100 Spectre (Running)
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- MFolks
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Sometime just running the engine for 100 miles will free up the rings.
Mopar makes a combustion cleaner designed to remove carbon build up: Mopar Combustion Chamber Cleaner # 04318001.
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- nads.com
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- larrycavan
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Get it running. Put some miles on it and see how it goes. It's likely the valve seals are going to need replacing in the near future anyway. That's the time to address and piston ring problems you may have.
If it's still got the stock pipes and airbox, leave them on it....
Larry C
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- testarossa
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- Attack life, it's only trying to kill you.
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Definantly change the oil, ring free, fresh plugs, clean points, probably clean carbs, and make sure that it has a new, clear, inline fuel filter so that any junk in your fuel tank doesn't clog up the carbs.
1978 KZ1000 A2 Click--->Build Thread
2004 ZX-10R
2007 Harley Sportster 1200
2020 Harley Street Glide Special
Angola, IN
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- 2KZLTDs
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Another question if you don't mind. I am trying to install a rebuild kit in the front master cylinder as well but can't seem to see how to remove old piston parts. I have Hayes manual and know that it has a snap ring but can't even get beyond the dust cover which seems to have a piston stop in a grove but no way to remove. Is there some trick or tool needed here other than snap ring pliers if I can get that far???
1976 KZ900B LTD (One runs, One rebuilding)
1980 KZ1300B (Next rebuild/may sell)
1983 KZ1100 Spectre (Running)
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- MFolks
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1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
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- bountyhunter
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I think you spray it in the spark plug hole and let it run down onto the rings.I will try the ring free after changing oil and checking points. Assume this is a additive to gas or spray with instructions but let me know if something additional on how to use is needed.
If not done, you need to remove the gas tank and rinse it clean. Also, clean the petcock assembly.
1979 KZ-750 Twin
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- mark1122
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- Keep twisting it
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there is also a product called Sea foam, that can be added to the oil and gas to free the rings and clean the carb and carbon.
76 KZ, frame gusset work,1200CC.Ported by Larry Cavanaugh, 1.5mm.over intakes, Carron Pipe, ZRX12 rear end, and seat,96zx9 front end.
01 CBR600F4i Track bike.
Cobourg, Ont. Can.
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~ (k) / (z)
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- DoubleDub
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Thanks guys for all the good suggestions . I have already put a set of kz1000's M26's on that had been cleaned / checked out so feel this is covered. I will try the ring free after changing oil and checking points. Assume this is a additive to gas or spray with instructions but let me know if something additional on how to use is needed. Knowing that it likely will start at this compression I'll give it a try and see what happens and let you know. Probably will wait and see on the value cover after this step testarossa.
Another question if you don't mind. I am trying to install a rebuild kit in the front master cylinder as well but can't seem to see how to remove old piston parts. I have Hayes manual and know that it has a snap ring but can't even get beyond the dust cover which seems to have a piston stop in a grove but no way to remove. Is there some trick or tool needed here other than snap ring pliers if I can get that far???
I used the master cylinder rebuild kit on my 900. I have a picture somewhere of the pieces apart so I could remember how to put them back together. I'll try to post it this evening.
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- 2KZLTDs
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I will check further with Z1 on the brake cylinder rebuild as I need someting to get the first piston stop out before I even get to the snap ring stage that they sell a tool for. Thanks again for all the help here.
Last question is do you guys know any good KZ900,1100,1300 mechanics in the mid Michigan area who are skilled in these old bikes and interested like you are? I now have four of these and could probably use some local help especially on the KZ1300 which I would like to tackle next????
1976 KZ900B LTD (One runs, One rebuilding)
1980 KZ1300B (Next rebuild/may sell)
1983 KZ1100 Spectre (Running)
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- DoubleDub
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