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What is the correct compression ratio for a KZ 900
- jerry chabino
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I have conflicting info on the kz 900 compression ratio. My compression ratio is 112 -115 hot across all four cylinders. Is this OK ?
I have heard the Clymer manual says 130 and another manual says 115. Sure could use some help on this. Bike has 9500 miles is runs really bad. I would hate to spend $$$$ on a rebuild when not necessary.
Thanks,
Jerry
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- KZJOE900
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Current project 76 KZ900 (This was a Vetter model)
76 KZ900
81 XJ550H SECA (Current Project)
82 XJ550R SECA
Past:
86 FJ1200
74 Z1900
72 CB450
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- taildragger1197
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Union City, Tennessee
1979 KZ1000 LTD B3
1979 KZ1000(1260)LTD S/G Pro ET
1993 ZX11 D1 Ninja
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- jerry chabino
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tnx taildragger
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- jerry chabino
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- Nebr_Rex
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jerry chabino wrote: Hello all,
I have conflicting info on the kz 900 compression ratio. My compression ratio is 112 -115 hot across all four cylinders. Is this OK ?
I have heard the Clymer manual says 130 and another manual says 115. Sure could use some help on this. Bike has 9500 miles is runs really bad. I would hate to spend $$$$ on a rebuild when not necessary.
Thanks,
Jerry
2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected
www.dotheton.com/forum/index.php?topic=39120.0
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- Motor Head
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- FIX UP YOUR BIKE RIGHT AND CHEAP
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1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- wireman
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Sounds like its time for rings atleast if the bores are still in spec,but If Im going to all the trouble to pull the top end off Id go ahead and have a real valve job done including new seals if the guides are still good.jerry chabino wrote: tnx Joe. When I added a teaspoon of oil to each cylinder compression jumped to the high 160 range
Dont forget to check cam chain and related stuff and atleast drop the pan and check oil pump pick up screen
posting from deep under a non-descript barn in an undisclosed location southwest of Omaha.
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- APE Jay
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Compression ratio is a mechanical number that won't change with engine wear, cam timing, oil in the plug hole. Cylinder pressure will.
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- 531blackbanshee
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for any internal combustion engine.
it takes 65lbs of compression to even create combustion.
a good number is the 140-160 lb range with a compression tester in five kicks with the throttle open.
if you are using oil to help your numbers you are grabbing at straws.
100 lbs of compression is time for a rebuild.
anything less is dieing a slow death.
this info is free,take it for what its worth,your mileage may very,caveat emptor.
leon
skiatook,oklahoma 1980 z1r,1978 kz 1000 z1r x 3,
1976 kz 900 x 3
i make what i can,and save the rest!
billybiltit.blogspot.com/
www.kzrider.com/forum/5-chassis/325862-triple-tree-custom-work
kzrider.com/forum/5-chassis/294594-frame-bracing?limitstart=0
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- baldy110
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- wireman
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This can also be the case,just depends on the circumstances and how much time/patience you have.baldy110 wrote: I have had engines with low compression numbers that had been sitting for awhile. The rings get stuck and after getting it running then running it for a few hundred miles the compression numbers would come up to normal.
posting from deep under a non-descript barn in an undisclosed location southwest of Omaha.
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