84 Interstate

[GL1-242]

I did a compression test on engine.
1= 150
2= 185
3= 42
4= 68
not much suction on finger when checking for TDC. My neighbor who is a true gearhead says if the valves where closing you would feel suction on finger.
Time to break into the heads and check the valves.

Paul

[robin1731]

Actually it's time to do a leakdown test. You aren't done diagnosing yet.

[DUGG]

Actually it's time to do a leakdown test. You aren't done diagnosing yet.

What he said, or do a wet compression test

[NotSoLilCrippseys]

You can save few bucks by taking the old cover off yourself and shaping the foam the way you want it.
Keep the cover though as they may want to measure it.

Gord

I agree with Gord. We took just this approach on an '83 build, and it came out pretty nice for the cost of some staples and some marine vinyl - and labor in the shop and at the dining room table. Given the shape we wanted, we didn't have to make a pattern, sew, or anything. 5000 miles in the saddle and it still looks like the day I put in the final staple.

[GL1-242]

guy behind me has a leak down tester but not a 12mm adaptor. I'm pulling the heads and going to clean up the valves and cylinder walls.

Paul

[gltriker]

guy behind me has a leak down tester but not a 12mm adaptor. I'm pulling the heads and going to clean up the valves and cylinder walls.

Paul

Motion Pro - 4-stroke Leak Down Tester Replacement 12mm Hose - 08-126Y

Paul,

I bought this Motion Pro 12mm adapter hose assy. on Amazon a couple of years ago. A real bargain at the time. $14 with Prime shipping. You really NEED one for diagnostic testing before disassembling an engine!
Can't locate just this single 12mm hose assembly in the Amazon listings now though.
It has Schrader type valve stem core threads already machined into the spark plug end of the Leak Down Testing hose assembly.

note: (a Schrader valve provision is not used anywhere in a Leak Down test rig)
It will quickly become a 12mm Compression Tester hose assembly, too, by simply installing a Schrader type valve stem core. Bonus!
Although it's difficult to see in the Motion Pro catalog picture, the air hose male adaptor fitting is already a permanent part of the hose assembly.
https://www.ridersdiscount.com/motion-p ... 2mm-172217
Readily plugs into my older Snap-On compression tester air coupler, my single gauge Kohler Engines cylinder leak down tester air coupler, and my shop air hose quick release couplers, too.

I will repeat......You really NEED one.....

[GL1-242]

Sweet thanks for the link.

Paul

[gltriker]

You are Welcome, Paul.

Although I haven't removed either cylinder head off my trike's engine , an occasional cylinder compression test and cylinder leak down test session is time well spent to keep an "eye " on my engine''s top end.