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getting my guage calibrated tommorow and want to check compression on my motor and want to get a couple questions answered on the proper procedure
i know the throttle should be wot and kick until the gauge stops moving
does the length of the hose make a difference
cold motor or hot?
do you test with or without crank case oil in her?
any other info appreciated
 

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cold motor is what I do. length of hose should not matter because it's usually reinforced. if an engine is turning over its good to have lube for any metal parts moving against one another. when I check compression the plug comes out, Guage goes in, open the throttle, kick it like 5 times, check the numbers, let the air out, and do it once more cuz it's fun.
 

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if you put oil in it before you try a compression test,it will show a higher reading.now some of the compression tester's have different lenght screw-in bung's.if you use a short one the comp.will be alittle lower than using a longer one.

throttel open,kick till the guage stop's moving.
 

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if you put oil in it before you try a compression test,it will show a higher reading.now some of the compression tester's have different lenght screw-in bung's.if you use a short one the comp.will be alittle lower than using a longer one.

throttel open,kick till the guage stop's moving.
Yup, WOT and "kick till guage stops moving"....x2

Carlos
 

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I always test with the cylinder dry 1st ( no oil added ) I take note of the reading. Then I put a shot of 2 stroke oil down the plug hole and check it again. If you see a change in PSI to the normal operating range, you know the rings are toast. On a 4 poker if you have a bump up to normal psi from a low psi with oil added you know your rings are toast and the valves are still good. If you have little to no bump in psi at all, its a valve job and piston and rings time.
 

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I tested with a "push in " and a screw in gauge, no change , even if one is taking all the spark plug cc...

Gotta say that some porting in order to run with pump gas will test at 150 brand new , so i dont think that 140 is a bad number. really depend on your cylinder/head/ ect. the best way to go is to take compresion test after breaking and then use this number as reference... a leak test is really accurate but its faster to just pop the head and check for cylinder wear (on a 2 stroke)


Best comrpession tester to get is the one with remote hose and "screw in" type, no need to be 2 guy to take compression test and push in can be real pain to seal on small spark plug engine... Canadian tire do sell inexpensive gauge and they do the job... not like you need a big fancy tester for testing compression once a month,
 
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