Lower Rear Cylinder Compression

[Mr. SeXieR]

My stock 08SXR is reading 10psi lower on the rear cylinder 175/165. Do ya'll like these numbers?... and is there a reason for the rear cylinder having lower compression? I also think I found soot or carbon on top of the exposed plug and inside the plug hood cap?? Anyone ever seen this? Am I getting some kinda spark inside? I changed my plugs and we'll see if It happens more.

 

[Shonuff]

I wouldn't worry too much about it but I would retest about every two weeks to see if the numbers are consistent.

 

[5810]

that soot is some top secret kawi grease that turns to crude oil when applied to spark plugs LOL.

u might have a air leak which cause your cylinders to score up and u lost compression.

mine read the same thing, pulled the head and found a nightmare.

 

[Mr. SeXieR]

air leak? elaborate please, its under warranty still so i'd like it identified asap

 

[fastony]

My stock 08SXR is reading 10psi lower on the rear cylinder 175/165. Do ya'll like these numbers?... and is there a reason for the rear cylinder having lower compression? I also think I found soot or carbon on top of the exposed plug and inside the plug hood cap?? Anyone ever seen this? Am I getting some kinda spark inside? I changed my plugs and we'll see if It happens more.

Are you using and good gauge I have not seen a stock sxr with 175 lbs. compression before. Try checking the compression cold and then check it hot, usually if you have a head gasket leaking it will show up when its hot. Be sure and hold the throttle wide open when you are checking compression.

 

[rollin5150]

My plugs and caps look the same. Pull them off the spark plug and they are black. I have had no issue in the two years they have been like this. Like Shonuff said, I probably would not worry about 10 psi difference. Could have been a better seal on the front plug hole vs when installed on the back plug hole. My stock compresion is at 150 on both.

 

[Mr. SeXieR]

thats the compression readings I got from the Kawi house, I know the guy there and his "forte" is stand-ups, his face lights up when I show up. when I first bought it last september they both read 175...?.... Ya'll think thats too high!?! Thought that high compression was a good thing?

 

[fastony]

thats the compression readings I got from the Kawi house, I know the guy there and his "forte" is stand-ups, his face lights up when I show up. when I first bought it last september they both read 175...?.... Ya'll think thats too high!?! Thought that high compression was a good thing?

No thats ideal compression but be sure and run premium gas in it, but if the showed the same compression new and now your down 10lbs. you might of had a small seizure on that cyl. or you might have a head gasket leaking. Retorque the head and check your compression cold and hot and see what you end up with. Are you below sea level that still puzzels me how you have that much compression on a stock ski?

 

[Mr. SeXieR]

naw, im in central Texas, maybe I just broke it in perfectly ))!!! Ive also ran Amsoil Interceptor since day one too.

 

[Shifty]

The suit on the plugs is normal, but I think you will notice less if you use "solid top" NGK plugs. Look at the pictures, solid top on the left and the more common variety on the right. I need to order some more for my ski since I can't get them locally.

On your compression test... Good charged battery, cold engine, shut fuel off, remove both plugs boots/wires and ground them, remove only one plug at a time and test that cylinder with the throttle held wide open untill the psi stops climbing (would test twice), replacing the spark plug in the cylinder you just tested before continuing to the next.

I wouldn't know whats up with your compression, I am going to visit jeff either this weekend or the next. I will bring my SnapOn Compression tester and we can compare your numbers with his if your around.

 

[Mr. SeXieR]

Ran it again, closer this time 175/170