Engine Compression Range?

[kumpy]

Just wondering what is consider healthy and normal for regular street bikes and for race bike with high compression.

2000 R6 regular gas
Cylinder 1: 176
Cylinder 2: 155
Cylinder 3: 175
Cylinder 4: 156

2002 GSX-R750 high compression is averaging about 170-180 for all 4 cylinders but I can't remember exact numbers.

[timmyho414]

Not sure of specs for your bike but as a general rule, 10 percent difference is ok, using your high that would be 17-18psi. You're a bit over that. I would not pull the motor apart for just that. Is there a reason you checked the compression? high mileage, lots of laps, burning oil, etc.

How do the plugs look?

[Degsy]

Wirelessly posted

Lol. He saw me do it and likes to fiddle and worry.

Lol. Love you kumpy!

:-)

[Degsy]

Wirelessly posted

Are all spark plugs out? Are you holding the throttle WFO?

[Kurlon]

Are your valves in spec?

[Stromper]

Do not seek what you fear to find

Was it warm ?
Tight valves
Old squirt of oil trick

[kumpy]

Wirelessly posted

Are all spark plugs out? Are you holding the throttle WFO?

All the plugs are out and held the throttle WFO just like you taught me!

- - - Updated - - -

Are your valves in spec?

Not sure if my valves are in spec, how do you check that?

[kumpy]

Not sure of specs for your bike but as a general rule, 10 percent difference is ok, using your high that would be 17-18psi. You're a bit over that. I would not pull the motor apart for just that. Is there a reason you checked the compression? high mileage, lots of laps, burning oil, etc.

How do the plugs look?

Plugs look dry, dark brown. Seemed to be normal looking. Reason I checked the compression was cause it has 12k miles, I got it used which there's always a concern, lots of laps through it, about 12 track days this year. I wanted to find out what kind of condition the motor is in. what are the reasons why people do compression tests?

[Eric Baker]

Usually you do compression tests if you have a problem with misfires that isn't spark related, or are consuming oil/coolant at an abnormal rate. These issues could indicate a bad head gasket or rings, which are more easily found with a compression and/or leakdown test.