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compression

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compression

Postby yamaha440 » September 10th, 2006, 2:08 pm

on my ski-doo citation i checked the the compression and it came out as 65psi is this good or not if not what should it be at its a 377 just wondering the same for my 440 exciter it came out as 85psi sounds ok thanks
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compression

Postby JBGabriel » September 10th, 2006, 2:25 pm

Usually anything under 100 psi will not run or will be very hard to start and be down on power. Compression should also be with 10% on each cylinder.
Jed

1971 Ski-doo Olympique 300
1980 Kawasaki Drifter 440 in a Honda Odyssey frame
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compression

Postby outagas » September 10th, 2006, 2:32 pm

anything less then about a 110 lbs, would be a bad thing.
has this motor been setting? has it been started up recently? perhaps your rings/cylinders are just dry, and you aint getting a good seal??? also, what kind of gauge did you use? trust me, if its a cheap one, I`d just about bet the farm, its not reading right. I tried two differant gauges from HF, and neither one read right (had a friends snap on, to compare to) and when I say, they did`nt read right, I mean one motor read 70lbs, when it actually had over 120lbs. funny thing is, BOTH these cheap gauges, read perfectly on a four stroke motor. strange huh..

basicaly, if it starts and seams to run good, you got more then 65psi. its probley your gauge giving a false reading, I dont even think you could get a motor to run on that low of compresion, its a general rule of thumb, that any motor, needs atleast 100 PSI to run worth a damn..four stroke included. not saying ya cant get one to go on less then 100psi, but.........
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compression

Postby outagas » September 10th, 2006, 2:33 pm

Hey JBG, I was typing that reply above when you posted, dont want ya thinking I was answering anyway, when it had already been answered..
cool that we both agree though..
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compression

Postby JBGabriel » September 10th, 2006, 2:55 pm

Not a problem. Great minds think alike.
Jed

1971 Ski-doo Olympique 300
1980 Kawasaki Drifter 440 in a Honda Odyssey frame
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compression

Postby Snowman1000 » September 11th, 2006, 2:06 am

Do you have the long hose type compression tester because they always seem to give low readings
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compression

Postby AHood » September 11th, 2006, 3:25 pm

[quote=Snowman1000]Do you have the long hose type compression tester because they always seem to give low readings[/quote]

correct you should get the kind thats short and threads right into the head ie no hose.
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compression

Postby ZR800XC » September 12th, 2006, 5:29 am

Does this thing run??? If it does, then who cares? The readings on the guage are just for comparison anyway, they have no real value. There's different tests that can be done. Dry test, Wet test...Their difference in percentage is what tells you if the rings are bad. Side to side, percentage as well. However...I'm thinking 65psi would be a bad thing if the guage is correct!


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compression

Postby yamaha440 » September 12th, 2006, 12:57 pm

Ya it was just a cheap one has a long hose they both run strong i just wanted to compare the two sleds how much money would a good one be thanks
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compression

Postby AHood » September 12th, 2006, 4:29 pm

[quote=yamaha440]Ya it was just a cheap one has a long hose they both run strong i just wanted to compare the two sleds how much money would a good one be thanks[/quote]
probably 35-50 dollars
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