Equally poor compression? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 13 (permalink) Old 05-31-2014, 08:46 AM Thread Starter
Crowley
 
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Equally poor compression?

Got a compression tester from autozone. Pulled a plug, and pulled the other three wires, and tested one cylinder at a time, and got just over 100psi in both cylinders.

Rear jug is burning oil.

I'm confused.
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post #2 of 13 (permalink) Old 05-31-2014, 10:58 AM
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place a tablespoon of oil into the spark plug hole and turn the enigne over several times then conduct your compression test as normal... if the compression goes back up, you have bad oil rings. If it stays the same you could have bad valve seals, or problems in the bottom end.
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post #3 of 13 (permalink) Old 05-31-2014, 12:31 PM
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i would do a leakdown test.
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post #4 of 13 (permalink) Old 05-31-2014, 09:05 PM Thread Starter
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I'm going to have to redo the test, because I got 140 psi out of one cylinder under separate circumstances.

I'll document the motorcycles variables before testing next time and post results.
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post #5 of 13 (permalink) Old 05-31-2014, 09:15 PM
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Quote:
Originally Posted by wmsonta View Post
i would do a leakdown test.
That is after he checks for bad rings... Since it's the fallowing step.

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post #6 of 13 (permalink) Old 05-31-2014, 09:19 PM Thread Starter
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First numbers will come from the bike as follows:

Cold motor, center stand down, throttle wide open, both shallow plugs out, both deep plugs in (I still can't reach them!)

I'll test rear jug first, then front.

This winter will be rebuild winter - take the motor out, check cylinders and rings, get heads redone, new Balance dampers....

Anything else I'm missing?

Last edited by crowley1027; 06-01-2014 at 11:38 AM.
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post #7 of 13 (permalink) Old 06-01-2014, 10:37 AM
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Quote:
Originally Posted by slimvulcanrider View Post
That is after he checks for bad rings... Since it's the fallowing step.

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A leakdown will find bad rings, you will get air from the crankcase breather. Lots of it.

If you are going to do more compression testing, have the throttle open.
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post #8 of 13 (permalink) Old 06-01-2014, 11:39 AM Thread Starter
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Edited last post to add throttle
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post #9 of 13 (permalink) Old 06-01-2014, 11:54 AM
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18mm deep well sparky plug socket from craftsman to get the plugs even the deep ones..

I forgot the exact part number. but its posted here in several places.. do a search

2005 VN750

Sold 11-27-17
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post #10 of 13 (permalink) Old 06-01-2014, 11:57 AM
..have a vulcan good day!
 
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Quote:
Originally Posted by michiganteddybear View Post
18mm deep well sparky plug socket from craftsman to get the plugs even the deep ones..

I forgot the exact part number. but its posted here in several places.. do a search
Sears will have 18mm "Thin Wall" Deep Socket hanging on the wall.


'86 VN750 13,700 mi -Stock
-Purchased 2008 w/8800mi
Replaced ALL Cables . Kuryakyn LED Voltmeter
SilverStar Ultra 9003/HB2 H4 Headlamp, Jardine Fwd Controls,
Iridiums DPR7EIX-9 & Wires, Tuxedo Mod, Coil Mod, P/U Sensor Mod, Fork Seals,
Splines Lubed - 11/4/2012 - MF AGM Battery
Additional Flashing LED Brake Light on Trunk
Dampers went out @ 13+K !
After TOC MCCT's..... so amazingly quiet I discovered a rattling heat shield on my stock exhaust !
...have a vulcan good day!
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