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1979 KZ1000 cylinder PSI
- Kitten Tooth
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"Cylinders 1&4 have 135 psi 2&3 are at 120."
Is this ok, or does it need a rebuild or something... I just sold this other bike to make the money to buy this, iv'e been waiting for ever and have been looking forward to this bike for a long long time now.. Can i buy this and have it run ok for a long time?
Thanks guys,
KT
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH
DO A BARREL ROLL!!
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- TeK9iNe
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- What did you do!?!
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Then, with an old air cooled bike, the compression should be tested HOT, like after a good 30min run.
I can almost guarantee that the compression would be much better, and likely much closer (within 10% numbers).
Those would be your baseline numbers.
Of course this guy wants to rebuild the engine, so he can make a $bundle$ off you, for a fairly easily performed job.
Do yourself a favor and get the bike back. Then BUY A MANUAL and start saving for some basic tools.
Good luck man!
PS. My buddy rode a 900 with barely 110 compression on all 4, for like 3 years.
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- sbc1320
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1980 KZ1000 LTD-B4(MK II engine) - Progressive suspension, MTC pistons, Dynojet Stage III, all wear items replaced, WFO paint scheme(1978), etc..
Past bikes- 2 1976 Kz900's, 5 1975-76 Honda CB750's, Honda 500 -4, Honda 250, Honda 125, Honda 100, Suzuki RM 250, Honda XL350, Kawasaki KLR 650, etc..
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- bountyhunter
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The service limit of compresssion on a 750 twin is 115 PSI (hot) not sure about the KZ1000, I thought they ran about 20 - 30 psi higher than the 750 twins. 120 - 135 might be servicable for a while on a KZ1000 (?).Well, remember that thread i put on here about a month ago saying i was gonna get a KZ1000 but im only 14? Well, i got some bad new i guess from my mechanic about the bike. He says that it has weak cylinders... Heres the message..
"Cylinders 1&4 have 135 psi 2&3 are at 120."
Is this ok, or does it need a rebuild or something... I just sold this other bike to make the money to buy this, iv'e been waiting for ever and have been looking forward to this bike for a long long time now.. Can i buy this and have it run ok for a long time?
Thanks guys,
KT
If valve gaps are OK and the compression is low, you either need a valve job or new rings (or both). First check the valve gaps and make sure clearance is good. If you can squirt some oil in the cylinders and the compression goes up significantly, that means the leak path is rings. If it doesn't go up, it's valves.
1979 KZ-750 Twin
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- Kitten Tooth
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1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH
DO A BARREL ROLL!!
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- porchev914
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I have a '78 1000 that had compression #'s from 70 to 130 when I bought it. She smoked a bit and used a little oil, but it always started up on the first kick and never missed a beat (till I dropped a tool down the cam chain tunnel ) I bet you'll be fine with 120-135 psi till you're ready to freshen her up!
FRANKEN Z!
1978 KZ1000 A2A with 08'Speed Triple SSSA and '06 GSXR1000 front end
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- Kitten Tooth
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Thanks guys
1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH
DO A BARREL ROLL!!
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- roy-b-boy-b
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I installed a motor last year and one cylinder had bad compression. I went to the bike shop and got some ringfree and mixed it with the next two tanks of gas and the pressure in the bad cylinder came up.
Roy
1979 LTD Street Fighter.1977 KZ1000
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- Old Man Rock
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Standard is 121 ft pounds.
Service limit is 85 ft pounds or a difference of 14 ft lbs between any 2 cylinders.
Based on the numbers you posted and in a non warmed up fully operational engine, you may be ok for the time being.
A leak down test would also inform you of some possible issues such as worn out rings & valve seating leakage...
OMR
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- Patton
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Well, remember that thread i put on here about a month ago saying i was gonna get a KZ1000 but im only 14? Well, i got some bad new i guess from my mechanic about the bike. He says that it has weak cylinders... Heres the message..
"Cylinders 1&4 have 135 psi 2&3 are at 120."
Is this ok, or does it need a rebuild or something... I just sold this other bike to make the money to buy this, iv'e been waiting for ever and have been looking forward to this bike for a long long time now.. Can i buy this and have it run ok for a long time?
Thanks guys,
KT
Sure wouldn't bet the farm on that mechanic's opinion. :pinch:
But can instead bet comp psi's are okay based on KHI's official FSM for 1979 KZ1000, namely:
Comp specs @ 128~156psi with service limit of 100psi and <14psi difference between cyls.
Some large four engines continue serviceable performance with even less than 100psi.
Imo, am concurring with others who suggested best to first assure valve clearances being to specs, and put some miles on your engine, before getting too excited about the measured cold comp figures, and difs between cyls.
Remember to change both oil and filter.
Good Fortune!
1973 Z1
KZ900 LTD
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- Kitten Tooth
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1981 Kawasaki KZ1000-K LTD
1983 Suzuki GS300L-D
1982 Suzuki GS300L-Z sold:(
1976 KZ400D3
1973 Z900... I WISH
DO A BARREL ROLL!!
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- roy-b-boy-b
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Leak down test can be found with the search function. Roy
1979 LTD Street Fighter.1977 KZ1000
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