compresion

[Z1Barrie]

what should the compresion on a z 900 ive measured mine they all aprox 79 psi... is that good or bad ad on start up from cold my number 4 cylinder pops back through the exhaust
any ideas

barrie


(Edited by Z1Barrie at 5:21 pm on May 26, 2006)

[chrisu]

sir is very low. book says 130-160. with throttle wide open

[DogsbolloxofZ1B]

As above, IMHO a few things I'd make absolutely sure of:

1) Is the gauge calibrated? Although all 4 cyls are reading low are they really. Calibrate against 8bar factory compressed air.
2)Is the 'O' ring seated properly.

If the above OK then I would redo the dry test and record results then add 10cc oil in each bore and compare. If its still low it could be sha4gged bores and OR valves not seating corectly. I assume the head gasket if fine? If it climbs towards 140psi mark then its an indication the heads OK.

Mike

[hanskloss]

Z1Barrie, just to make sure , you measured the compression on a warm engine, have you?

[Z1Barrie]

WELL ID SAY LUKE WARM TO COLD WHAT SHOULD I HAVE TESTED IT ON A COLD OR HOT ONE...

CHEERS IN ADVANCE

BARRIE

[hanskloss]

warmed up to normal operating temperature, best just take the bike for a spin , if you test on a cold engine compression figures will be lower

[Rich]

Check your shim clearances before you do it.
Warm engine, remove all plugs, check compression on WOT, if still low,put a couple of squirts of oil into the bores, if it dramatically rises then it's rings, if it stays the same it's valves.