[goldwingnut]

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HI ALL . WISCONSIN USA . 1980 GL1100I .I HAVE READ OVER AND OVER THAT MY BIKE SHOULd HAVE AT LEAST 140 COMPRESSION. MINE HAS 95 ON ALL FOUR . BUT IT STARTS BEAUTIFULLY IN 25F WEATHER OR 90F WEATHER . I THINK IT RUNS GREAT. I THINK THE LEFT COIL IS WEAK THOUGH. I HAVE TAKEN THE READING WITH OIL IN THE CILYNDER AND GET 120 . IS IT POSSIBLE TO RUN GREAT ON THAT LOW OF COMPRESSION?

 

[Crankcase1943]

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You say it runs great. Does it crank when hot?Does it use any oil? If it does crank easly and don't use oil don't worry about it.

 

[norman]

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Hi Goldwingnut

Did you hold the throttle wide open when doing the comp. test ? If the throttle isn't held wide open it will read in the 80's to 90's.

Good Luck and good riding

Norman

 

[goldwingnut]

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IT HAS ABOUT 80,000 MILES . CRANKS EASY WHEN HOT.BURNS ABOUT A PINT EVERY 3000 MILES. I DIDN'T OPEN THE THROTTLE WHEN CHECKING. THANKS FOR THE POINTER.

 

[exavid]

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goldwingnut wrote:

IS IT POSSIBLE TO RUN GREAT ON THAT LOW OF COMPRESSION?

Don't shout. It must since yours is. You do have all the spark plugs out besides having the throttle wide open? It wouldn't hurt to run it a bit first, a warm engine will give a more realistic reading. I suspect you're getting a bit of a false reading one way or another, especially with all four down to 95 and even. Usually worn rings don't wear the same in all four holes.

 

[goldwingnut]

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ALL PLUGS WERE OUT AND I TRIED IT BOTH HOT AND COLD.I STILL DIDN'T HAVE TIME TO TRY THE THROTTLE OPEN. THIS WEEK HOPEFULLY.

 

[goldwingnut]

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I checked the compression with the carbs off. I cleaned the carbs. Compression was 178 on #3 and 180 on the rest. no wonder it runs good. The throttle surely does have to be open for a correct reading.

 

[BigAl]

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Well done, that's definitely a very healthy compression. Nothiong to worry about there.

 

[knot750]

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When the compression goes up after putting oil in the cylinder, that indicates worn piston rings. It may run great but it will be missing some power and economy.

 

[exavid]

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goldwingnut wrote:

I checked the compression with the carbs off. I cleaned the carbs. Compression was 178 on #3 and 180 on the rest. no wonder it runs good. The throttle surely does have to be open for a correct reading.

Yep, very good. Actually a little higher than new but that might just be a bit of carbon buildup increasing the compression ratio a wee bit. The differential among the cylinders is very good. I suspect the oil burn is coming from worn out valve stem seals.

 

[ROCKANDFINISH]

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can u check compression with carbs off?

 

[ROCKANDFINISH]

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81 goldwing 1100 had vaperlock filled 3 cylinders up with gas took carbs off and going to rebuild just wanted to know if I had to put them back on for compression check

 

[goldwingnut]

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No you don't need the carbs on to check the compression.