Compression check. Does not make sense.

[hereismylife]

As I am checking things out before next snow here I figured I would check the compression in my 3 sleds.

Checking

Cold engine
Wide open throttle
All plugs removed
All sleds are pretty close 75 - 90 psi

I checked my gauge with air compressor and it is dead on with psi. Checked up to 120 and it held. All sled run fine. one sled only has 2000 miles others around 4000.

What do you think why compression is so low?

 

[Terrence R]

As I am checking things out before next snow here I figured I would check the compression in my 3 sleds.

Checking

Cold engine
Wide open throttle
All plugs removed
All sleds are pretty close 75 - 90 psi

I checked my gauge with air compressor and it is dead on with psi. Checked up to 120 and it held. All sled run fine. one sled only has 2000 miles others around 4000.

What do you think why compression is so low?

That is odd. I know u said that u checked your tester, but maybe try one of your buddies testers and see what happens. I've heard stories about certain oil causing compression problems ( I don't know if I should believe those stories or not). Do u run the same oil in all 3 machines?

 

[hereismylife]

That is odd. I know u said that u checked your tester, but maybe try one of your buddies testers and see what happens. I've heard stories about certain oil causing compression problems ( I don't know if I should believe those stories or not). Do u run the same oil in all 3 machines?

Yes all Amsoil. I am still checking things out. Has to be something with gauge. I am still open to all options

 

[super1c]

How long is hose? How hard are you pulling? Cylinders wet, dry? How cold out is it ect, ect..... Its not about the numbers within reason. Its how far apart they are!!! When you test your tester you are using a compressor that can hold the psi the entire length of the hose for a indefinite time. A piston stroke is but a few seconds to achieve PSI. Every tester is different and every puller is different ect.... This test is for a simple test to see if you have compression and that its equal. If one cylinder is 95 and the other 75 you have a problem. 95-95 all good. I just do a simple comp test every fall before i start winter prep. All my vipers are the same evey year. Now then i know if i do it at a later time and one cylinder is 10psi lower i got a problem. The numbers themselves are useless! The only real way to test the rings and comp is with a leakdown test. THat will give you a true reading of your rings. Judge each sled as its own set of reference numbers and you will be fine.

 

[Terrence R]

^^^+1. Also, I forgot to ask: how many pulls are u doing for each jug? I usually do 5 evenly firm pulls.

 

[hereismylife]

UPDATE...

After checking things out. I found out my shrator valve in the hose needed replaced. long story. Anyhow now it works. here are the pics for my 2001. I pulled it 10 times.

 

[TopGunnSrx]

Looks good....run it!

 

[super1c]

MONEY!!!!! Have fun and let it rip!!