What's the best way to compression test a Big Twin by yourself? What's the best tool? Do you leave one spark plug tightened in the motor, while you test the other cylinder with a (tapered) rubber tip compression gauge from Pep Boyz? Gotta be something better and more positive than that. How about a gauge where the needle freezes at the highest point of compression? Where can we find one?
I'd like to use a compression test to see how tight everything is with the rings. My cylinders have about 26K on them and are scuffed some at the rear of each. I'd like to test for pressure difference, do my on calculations, check out the (solid lifter) tappet bearings and run the motor another 10K, before I do any bottom end work. I have new heads.
Compression Testing
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Please do not start new topics here, but here: New Panhead and Flathead topics
Please do not start new topics here, but here: New Panhead and Flathead topics
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compression testing
My compression tester has a check valve that holds the reading, and it screws in to the spark plug hole. I probably got it from JC Whitney or someplace like that. Get a compression tester like it so you can screw it in to one head, leave the plug out of the other head and just kick the bike over a few times until the needle stops moving.
Don't use that pep boys compression tester you described, it would work on a car but useless on a two cylinder engine.
Don't use that pep boys compression tester you described, it would work on a car but useless on a two cylinder engine.
Thanks. I'm cruising over to Roebucks....and check out what they got.
http://www.sears.com/sr/javasr/product. ... +Equipment
Looks maybe more simple than what JCW offers. Less connections to leak maybe. Cheaper. I can pick it up at the local Sears outlet. Call first of course.
http://www.sears.com/sr/javasr/product. ... +Equipment
Looks maybe more simple than what JCW offers. Less connections to leak maybe. Cheaper. I can pick it up at the local Sears outlet. Call first of course.
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Just to reinforce what Kell said: there is no good reason to leave the other plug in. All it's gonna do is make it harder for you to turn the engine over. The pressure in one cylinder doesn't affect the other (well ... possibly, if you have some serious blow-by on both cylinders, but your engine would probably be shot at that point). So get the screw-in type with a check-valve and stomp away. It may help to note how many kicks it took to reach max. pressure, and compare cylinders. But if doing that you have to compare apple to apples, and start each kick from about the same position in the crank rotation, about equal pressure on your stomp ... and etc. And by that time you are probably gettin' as anal as I get sometimes, and will then realize that doing it the normal way works just as well.
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