Compression Tester Question

[Carl Walichnowski]

Ok so all the new parts are put on my bike and it’s finally up and running again since my accident. So now that I’m at the point where I was back in July when I broke my leg and tore my knee to s**t.
So I want to run a compression test, the question is not only what a perfect reading would look like but also what’s a good compression tester to buy? The Harbor Freight one is supposed to give unreliable results so what’s in line for the next cheapest that actually works??

 

[Street Ryderz]

Just like a torque wrench a good one comes with it's test data and who signed off on it's acuracy.

 

[Street Ryderz]

It's almost impossible to tell you what is perfect too many variables,you should however see at least 140 psi it's new right?

 

[Frankenstein]

Just for kicks I'd see what autozones free lender tools would say compared to hf brand. I could imagine a simple jig could be made test a comp tester on a pressured chamber that has a schrader valve bedded in it, just put a tire gauge on it. Epoxy and a spare cylinder head would be a good starting point.

 

[gary55]

I got two of the Harbor Freight Pittsburg ones. Thought maybe the first one being a piece of s**t might be a fluke. Nope, both crap. Bought a Bosch one from O'reillys. Works great.

 

[butre]

there isn't a perfect reading with them, but I like to see around 200 psi in my modified bikes. I'd have concerns if a stock one cranked less than 90.

 

[gary55]

Ok so all the new parts are put on my bike and it’s finally up and running again since my accident. So now that I’m at the point where I was back in July when I broke my leg and tore my knee to sh*t.
So I want to run a compression test, the question is not only what a perfect reading would look like but also what’s a good compression tester to buy? The Harbor Freight one is supposed to give unreliable results so what’s in line for the next cheapest that actually works??

I'm guessing your engine is still pretty new. What engine kit did you buy. And is it a slant head.

 

[inspectorcritic]

Ok so all the new parts are put on my bike and it’s finally up and running again since my accident. So now that I’m at the point where I was back in July when I broke my leg and tore my knee to sh*t.
So I want to run a compression test, the question is not only what a perfect reading would look like but also what’s a good compression tester to buy? The Harbor Freight one is supposed to give unreliable results so what’s in line for the next cheapest that actually works??

Don't throw your money away you'd probably use it once every 5 years got to O'Rieley's auto part store hand over your ID ask for compression tester.
Or drop by a mechanic shop ask if they can check for nothing. Most mechanic are amazed that you built your own bike be please to help your talent.

 

[Carl Walichnowski]

My motor is a Grubee Skyhawk and it has a brief summer of useage on it. I previously had compression issues due to two of the thread patterns being stripped in the lower end. In July I was taking the bike to be fixed, to have two helicoils put in when I was hit by a car. So I now have new forks and handle bars put on and I started fixing the original issue. The helicoils are put in and I used copper gaskets and I believe the Head was torqued down to the right psi (what that actually is I forget though). I have yet to ride it cause it’s getting repaired elsewhere but I figured the next step was a compression test. What do you guys think?

 

[crassius]

usually if you hit 125 cold compression with throttle held open, you're good to go - seen many at 110 that ran good but struggled a bit with steep hills