[ShadowRider55]

I have a 2002 Kawasaki Vulcan 750. Been restoring her for over a year now. I originally had no compression in the front cylinder, turned out to be a bent intake valve. Replaced it and cleaned up all the other valves. Now I get 65 psi on the front cylinder and 120 on the back. I would like to get the front cylinder psi to match the back. I have read some bikes have a compression release, not certain if mine does. I plan to check the rings with the oil test tomorrow. Any other thoughts on what to check? Would this be a normal reading if it does have a compression release?

 

[Eye_m_no_angel]

I haven't worked on a Shadow 750 in about ten years and I don't work on metrics now very often at all so I'm not an expert, but I don't see any reason for an automatic compression release on an engine like that. It doesn't have a manual compression release.

Do your wet compression test and see what you get, and take it from there.

 

[Ray'ssporty1200]

That always worked for me, did a dry 1st, then put about a tablespoon of oil into plug hole, if compression went up somewhat, that piston needed a ring job, if not, then it needed a valve job. If engine would only 'fire' with gas in plug hole, carbureytor was not adjusted right. Well that was about 35 to 45 yrs ago. . .

 

[SemiFast]

Best I can remember that bike doesn't have a compression release.
However it does have hydraulic valve lash adjusters.
The adjusters need to be pumped up (filled with oil) on assembly for them to work correctly.
You may want to look to them as a possible cause of low compression.

 

[ShadowRider55]

Just ran the wet test by putting a teaspoon on 10w-40 in the front cylinder. It jumped up to 90psi. Is a difference of 30psi a sign of a bad piston ring?

 

[Eye_m_no_angel]

Yeap, that's the most common reason.

If you can do a cylinder leak down test that can confirm your suspicions. If it's a valve adjuster issue, as Semi-Fast said, it can likely tell you that too.