Leak Test


Information and questions on GL1500 Goldwings (1988-2000)
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auditray2007
Posts: 13
Joined: Sun Nov 01, 2009 6:01 pm
Location: Galway, Ireland
Motorcycle: 1989 1500 GL

Leak Test

Postby auditray2007 » Sat Nov 06, 2010 10:36 am



Have to do the tranny thing on my 89 1500 GL and decided to do a compression and leak down test before stripping the beast.
Couldnt do a com test as the kit didn't have a 12mm adaptor.
Did the leak test and at first all cylinders showed almost flawless results (All remained in the "Set" zone) so good that I decided to do it again. On no 5 & 6 cyl I heard a pop and the needle droped to the dead zone. Air was flowing out through the left carb. I tapped the inlet valves but to no avail. Needless to say I didnt retest the other 4 just in case. Do anybody know what happened here??



ekcyclerepair
Posts: 46
Joined: Sun Jul 19, 2009 9:53 am
Location: Salisbury, NC
Motorcycle: Various

Re: Leak Test

Postby ekcyclerepair » Sat Nov 06, 2010 8:52 pm

I wonder if the popping noise was just the piston being forced back down by the compressed air. This could rotate the engine to a position where the intake valve would be open, which would explain the gauge going to zero, and the air flowing out the intake and through the carb.
One question though. Are you saying that air is flowing out of the left carb. when you pressurize the #6 cylinder, and also flowing out the left carb. when you pressurize the #5 cylinder? Cylinder #5 is on the right rear, so it should be flowing air out of the right carb.
Have you tried setting the 5 & 6 pistons at TDC again and rechecking the leakdown?

Ernie

auditray2007
Posts: 13
Joined: Sun Nov 01, 2009 6:01 pm
Location: Galway, Ireland
Motorcycle: 1989 1500 GL

Re: Leak Test

Postby auditray2007 » Sun Nov 07, 2010 10:31 am

Thanks for the reply.
I was aware that the crank could turn and cant't honestly say if I checked to see it was still lined up when the gauge hit zero (Lots of stuff going on at the moment). I hope that is the case. I must have being so seduced by the inital good readings to pay proper attention. I also made a mistake :oops: in my original post; it was No 6 & 4 and thats why I was concerned I suppose. I hope its the crank that moved as opposed to head gasket even though I will be replacing it anyway. I will retest tomorrow!

auditray2007
Posts: 13
Joined: Sun Nov 01, 2009 6:01 pm
Location: Galway, Ireland
Motorcycle: 1989 1500 GL

Re: Leak Test

Postby auditray2007 » Wed Nov 10, 2010 11:56 am

I did the test again and watched TDC carerfully and the air still went up through the left carb.
So after seeing the cylinder liners I guess my thoughts of compression leaking from cylinder 6 to 4 and then out the carb goes out the window.
I removed and turned the cyl head upside down and poured some petrol onto the valve heads and it leaked out the inlet and exhaust ports. I removed the camshaft holder thus taking the pressure off the valves and redid the test and little to nothing came out the ports. Does this mean that the problem lies within the hydraulic adujesters and why would this happen all of a sudden. As stated already the leak down test was perfect at first and whilst checking No 4 cyl again I heard a pop and then the gauge went to zero?

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WingAdmin
Site Admin
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Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
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Re: Leak Test

Postby WingAdmin » Wed Nov 10, 2010 1:24 pm

Is it possible that someone shimmed them incorrectly? Or that some sludge is clogging one of the lifter channels?

auditray2007
Posts: 13
Joined: Sun Nov 01, 2009 6:01 pm
Location: Galway, Ireland
Motorcycle: 1989 1500 GL

Re: Leak Test

Postby auditray2007 » Wed Nov 10, 2010 3:59 pm

Don't know. The bike was running well before I did the test. I will be taking the cam holder apart tomorrow.




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