i do cold compression test by hand all the time at work. im a senior tech at a ford dealership. if your bike is blowing blue smoke only on start up a cold test can really help because most pistons are eccentric and swell to a perfect circle with heat so if sompression is only low on intial start up a cold test will help diagnose between rings and valve guide seals which dont expand.with our cars i can but a 18mm soccket and snap on extended 3/8 ratchet on the crank bolt and turn a 6.8 liter v 10 by hand no problem so a 1.3 liter or less bike motor should be easy. just take off the clutch cover remove the actuating rod on the clutch and turn it right on the lock nut there as long its in gear cus your on the tranny side.
I was thinkin' about this last night (while contemplating the best way to destroy a GS500) and thought "well technically it should work". I've never tried it but it concept it should work, but how accurate would the reading be?
all right guys here is whats going on, on my end. a few weeks ago i pulled my motor apart to reshim my valves and clean the carbon build up that i new i had. the other day a coworker to me he said had the gauge if i ever needed it. if it's something that can be done by hand i figure it would be a small job and not hard considering the motors on the bench so, why not do it. i don't know a hell of alot about bike motors but in theory while it won't be dead on i would think it would be close enough to make sure i didn't have a major issue (a freind on mine did his after a rebuild and had 30 in one cylinder, this is what sparked my interest)
my ratchet is 3/8 drive and maybe a foot long. nothin major. just do it. but do it relatively, check all and if all are the same around 80 or whatever be happy. if 3 are 80 and one is 30 then something is up. motors dont typically wear out in unison on all cylinders. if there is a problem, 1 is typically off. i checked mine on my bandit 12 and got around 90ish on all. if one is lower then due a wet test. take your gauge out and give a drizzle of oil in the cylinder this will lube the rings and seal them better, if the compression comes up then you have bad rings if not then it could be burnt valves( carbon deposits on the face not allowing them to close all the way), bent valves( highly unlikely except with previous motor damage), bad valve guide seals( these will be also accompanied by blue exhasut smoke because oil slides by the seals into the cylinder and burns, also you may have compression coming out the oil fill, but bad rings can make that happen to). just test it and tell us
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