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Low compression
- karoliens
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83' Kawasaki KZ750E-L2
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- pete greek1
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Pete
1980 LTD 1000..,1976 LTD 900, have the 1000&900 now. the rest are previous= 1978 KZ 650 B.., 1980 Yamaha XT 500..,1978 Yamaha DT 400.., 1977 Yamaha yz 80..,Honda trail ct 70.., Honda QA 50...5-1/2 hp brigs & straton CAT chopper mini bike...3-1/2 hp mini bike (WHEN GAS WAS ABOUT 45 CENTS A GALLON)!!!!
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- kaw-a-holic
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Jon
1977 KZ1000a1
Mesa, AZ
Phoenix Fighter Project
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- karoliens
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pete greek1 wrote: Did you check it with WOT ?
Pete
Yes.
83' Kawasaki KZ750E-L2
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- zed1015
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If one was significantly lower ( more than 15psi off ) then there would be reason to suspect a dodgy valve or piston ring etc.
Probably time for a good overhaul and re-bore .
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
kzrider.com/forum/23-for-sale/611992-air-corrector-jets-
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- 650ed
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1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- karoliens
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650ed wrote: As kaw-a-holic stated do a leak down test. That will point to the compression leak(s). Check Pep Boys, Advance Auto, and Auto Zone loaner tool programs. At least one of those stores will have or will order set of leak down gauges that you can borrow. Ed
83' Kawasaki KZ750E-L2
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- Patton
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Can perform a poor man's leak down test by introducing compressed air into a spark plug hole and listening to where it escapes from the combustion clamber. This may be done at TDC or any other cam positions where both valves are fully closed. Top dead center (TDC) is when the piston is at its highest position. An easy way to tell TDC is by alignment of the T mark with the case mark when viewed through the timing window.
May introduce a spurt of compressed air by using a rubber cone-tip blow gun (rubber air nozzle) held into the spark plug hole. And of course keep holding it in position to keep air from coming back out the spark plug hole while listening for escaping air at other places. The air compressor should not be running while listening because the noise will likely drown out any sound of escaping air. Or just use a portable compressed air tank.
Air heard escaping from exhaust port indicates exhaust valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).
Air heard escaping from carb intake indicates intake valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).
Air heard escaping from crankcase breather indicates loss of compression past rings into crankcase (perhaps worn piston rings or cylinders).
Air heard escaping from head gasket area indicates indicates loss of compression past head gasket (perhaps due to a blown head gasket).
A leaking valve may sometimes be resolved by adjusting the clearance to within specs.
A leaking head gasket may sometimes be resolved by torquing the head fasteners when the engine is stone cold (such as after sitting overnight).
Good Fortune!
1973 Z1
KZ900 LTD
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- Patton
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karoliens wrote: So I checked compression of my KZ750E-L2. And bad news 90-95-85-85 PSI. The quastion is how to check if it is head gasket,,,,
Here's one way to help positively identify the exact point of oil leakage ---
Thoroughly clean engine and allow to fully dry.
Spray foot powder over edges of head gasket, valve gasket, half moons, tach drive, tach drive, exhaust ports, oil cooler lines.
Basically, cover top end of the clean dry engine with white foot powder.
It will appear almost as "painted" white.
Using a flash light or shop light, start the engine and inspect closely for the first sign of emerging oil, which will darken at point of leakage.
Good Fortune!
1973 Z1
KZ900 LTD
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- daveo
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650ed wrote: As kaw-a-holic stated do a leak down test. That will point to the compression leak(s). Check Pep Boys, Advance Auto, and Auto Zone loaner tool programs. At least one of those stores will have or will order set of leak down gauges that you can borrow. Ed
Using an air compressor hose (rubber tip) option, how much air pressure is safe to use for this procedure?
1982 KZ1100-A2
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- Patton
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Our home-owner's air compressors generally produce 100-120 psi, which is less than many stock engine compression ratios, and should be safe for the poor-man's version of the leak-down test.
Am uncertain about how much air pressure can be reliably held inside the cylinder when hand-holding the rubber-cone-tipped gun into the spark plug hole, before the air starts leaking and hissing back out around the rubber cone tip.
The poor-man's leak-down test can be successfully performed with less than 100 psi, as the idea is to listen for escaping air.
A portable air tank will drop to considerably less than 100 psi when used for the poor-man's leak-down test, yet still provide meaningful results as the pressure reduces.
Would not recommend using a 3200 psi scuba tank for the pressure source. :whistle:
Good Fortune!
1973 Z1
KZ900 LTD
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- zukdave
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1980 KZ650 F1
ZX750A1 motor.
Wiseco 810cc kit.
Zukiworks racing ported head.
VM 29 smooth bore's.
Dyna 2000 Ign. w/Dyna mini coil's
APE cylinder stud's and nut's.
APE valve spring's.
APE Track King clutch.
V/H KZ1000 sidewinder.
3.5x18 laced to a KZ1000 disk hub.
150/60/18 Shinko 006 Podium.
63" wheel base.
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