Do you have access to the equipment for a leak down test?
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another low compression question
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Vince, If the petcock is leaky the cylinders could be washed down with fuel. Pull the plugs, spin it around some, squirt some oil in the cylinders and test again.sigpic
09 Kaw C14 Rocket powered Barcalounger
1983 GS1100e
82\83 1100e Frankenbike
1980 GS1260
Previous 65 Suzuki 80 Scrambler, 76 KZ900, 02 GSF1200S, 81 GS1100e, 80 GS850G
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Yup, I am aware of that one Bob, no gas in the oil or carb throats at the time. The tank has been off since. Going to oil up the cylinders, maybe tomorrow and see what I get.
Thought this problem was a curious one as well.
Consider that I have completed all the obvious tests, this one has me stumped because there was no warning or symptoms prior.
VGustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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The only way I know of to lose compression quickly is to burn valves, but that won't happen without the valves being too tight, and it wouldn't be all 4 cylinders so evenly.
Holing a piston is another possibility, but that would be zero compression. Curious to find out what you learn when you do the leak down test.
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I don't have a tester for a leak down test so I won't be able to give you any feedback on that one.
Am in the middle of a construction project at this time, so wrench time is at a premium at this time.
VGustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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Well I finally pulled the head on the engine, it is shot, the exhaust and intake cam journals are wore out, look at the #1 journal. Will try and get some measurements and post them.
Gustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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I don't know, Vince. Hard to tell from the pic, but from here that doesn't look bad enough to affect the compression. But since you already have it that far, might as well pull the head and the jugs and have a look around. 16 Valve 1100 heads are in pretty high demand, might be cheaper to get a whole running bike and give me that onesigpic
09 Kaw C14 Rocket powered Barcalounger
1983 GS1100e
82\83 1100e Frankenbike
1980 GS1260
Previous 65 Suzuki 80 Scrambler, 76 KZ900, 02 GSF1200S, 81 GS1100e, 80 GS850G
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That head looks pretty normal and, as stated by tkent02, the wear on those cam journals would not effect compression. When you did the compression check, are you sure that you had the throttle held wide open the whole time? How quickly did it turn over? Did you have all the plugs out when doing it?http://img633.imageshack.us/img633/811/douMvs.jpg
1980 GS1000GT (Daily rider with a 1983 1100G engine)
1998 Honda ST1100 (Daily long distance rider)
1982 GS850GLZ (Daily rider when the weather is crap)
Darn, with so many daily riders it's hard to decide which one to jump on next.;)
JTGS850GL aka Julius
GS Resource Greetings
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Trust me guys the journal on #1 is SHOT. I will try and get a better close up and pics of the caps as well.
VGustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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Originally posted by tkent02 View PostNot saying it isn't wasted, but it could be completely eaten away, it will not effect compression if the cam is in there turning.
VGustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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Well, Gustov might be heading quickly to senility, but he's a machinist, so I trust his judgement on the cam journals. i also doubt he's forgotten how to work on bikes
So, give us some more clues1978 GS 1000 (since new)
1979 GS 1000 (The Fridge, superbike replica project)
1978 GS 1000 (parts)
1981 GS 850 (anyone want a project?)
1981 GPZ 550 (backroad screamer)
1970 450 Mk IIID (THUMP!)
2007 DRz 400S
1999 ATK 490ES
1994 DR 350SES
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Originally posted by smilinbrad View PostIf I lost all compression in all 4 cylinders at once on a recently running engine I would suspect my compression tester or my technique was shot
My best guess on the lost compression is a complete head gasket failure some how. Have not removed any valves yet to determine their health yet. There are no holes in the pistons and no sign of ring failure as well. The exhaust headers showed good burn on 2-4 and #1 running rich.
If my life settles a little I will get more and better pictures.
VLast edited by gustovh; 04-09-2016, 03:05 AM.Gustov
80 GS 1100 LT, 83 1100 G "Scruffy"
81 GS 1000 G
79 GS 850 G
81 GS 850 L
83 GS 550 ES, 85 GS 550 ES
80 GS 550 L
86 450 Rebel, 70CL 70, Yamaha TTR125
2002 Honda 919
2004 Ural Gear up
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