compression test

[hotrodbelair]

i just did a compression test on my 440 tonite and it only cranked out 45 and it was in the red green was way the hell up around 120 psi. and on the chart 45 aint any wheres near 8.0 now i never used a compression tester so does anyone know what this is

[Chino886]

Originally posted by hotrodbelair
i just did a compression test on my 440 tonite and it only cranked out 45 and it was in the red green was way the hell up around 120 psi. and on the chart 45 aint any wheres near 8.0 now i never used a compression tester so does anyone know what this is

I think that is low, but you might want to check with someone else. I think mine was higher than that and I am at about 11:1.

[hotrodbelair]

my dad used this one on his old snowmobiles is there a difference between the ones for 2 strokes and 4 strokes

[honda92]

compression testing equipment is the same for 2 or 4 stroke. did you hold the throttle wide open while you cranked it over? i would think you would atleast want 130-135 psi.

[FoxMxRiders]

this is important to leave the choke Off,throttle WOT and push the start button like 3-4 secondes

[hotrodbelair]

thanks for the info i didnt hold the throttle wide open ill try it tommarrow

[mikeboone]

Originally posted by hotrodbelair
i just did a compression test on my 440 tonite and it only cranked out 45 and it was in the red green was way the hell up around 120 psi. and on the chart 45 aint any wheres near 8.0 now i never used a compression tester so does anyone know what this is

Could be the probe wasen't seated in sparkplug hole fully?

[hotrodbelair]

i had it in there all the way while my brother cranked it over no air seaped out while i was doin it tommarrow ill do it again with the throttle wide open

[blackwell17]

k so equipment is the same if its a 2 stroke or 4 stroke?

[honda92]

it doesnt matter if it is a 2 or 4 stroke

[phildogg]

I'm pretty sure an engine needs atleast 90-100psi to even fire and run.45 sounds way to low.maybe check it again like stated above.
phil

[hotrodbelair]

i did it again today with same results with the throttle wide open but i think something is wrong with the tester i tried it with the throttle wide open and air seeped out and it was 45 tried it again no air seaped out and still at 45 so im gonna try my friends tester that he just got and should get different results i dont realy care if its low on compression cause im rebuilding the motor anyway once i get more money saved up

[jamienlogan]

I checked mine and I am putting out 100. I thought I should be putting out more than that, but the machine runs well though. I have a 440 11:1 piston.

[hotrodbelair]

yea thats where i was thinking mine should be is around 100 but u would think if it realy is 45 u would think it wouldnt even start on that and be able to wheelie in 3rd gear

[mikeboone]

Originally posted by hotrodbelair
yea thats where i was thinking mine should be is around 100 but u would think if it realy is 45 u would think it wouldnt even start on that and be able to wheelie in 3rd gear

If you have air seeping out when you hold throttle wide open {or not) you may have bent valve.

What you really need is a leakdown tester. This device hooks to air comp and fills the cylinder with air and you can hear where the problem is. If it comes out the carb the intake/s bent and out pipe one or more exh valves bent.

[hotrodbelair]

dont say that lol. it was leaking out the spark plug hole wasnt leaking out anywheres else

[honda92]

either way with 45 psi the thing shouldn't run. if it does run now, you testing equipment is screwed up. if you try another tester and get the same results, go and do a leak down test like stated before.

[hotrodbelair]

ive havent been on here in a while cause i was gone all weekend with a friend looking for fourwheelers. i did another compression test with a different tester with the throttle wide open and it read around 115. another thing i bought this quad from my brother not to long ago and he bought it last winter from someone. my brother doesnt no anything about whats done to it only thing he knows thats in it is a 440 wich riding it u can tell its got that but not realy sure about whats all its got in it like what compression or if its got cams.

[jamienlogan]

I thought I should have more than 100? Does that sound weak for a 440 to anyone?