How I got the Harbor Freight Compression Tester Working!!!

I bought the Harbor Freight Pittsburg compression tester to use on my motorcycle but it wasn't reading correctly. After a little research and seeing a lot of comments and videos to never buy this device I was sure I could make it work properly with some simple modifications. And sure enough I did.
The parts needed that I bought are as follows...
0.2-3 PSI opening pressure Schrader valve - www.ebay.com/i...
Update:The above link is no longer available on ebay however the Lisle 20100 or Milton 1251-2 valves cores will work
www.lislecorp....
www.miltonindu...
Schrader valve tap - www.ebay.com/i...

[@steelcityrailroad5095]

I just borrowed my friends and tested my sons motorcycle, was only getting 50psi. Then I tested my mower, it runs great and like new condition l. It was only getting 50 psi. I thought I had to rebuild everything I own after using that darn thing! Now that I am here, I completely understand. Thank you for your video!

[@werdevo6]

I too, also had the 60 psi syndrome with my new HF compression tester while reading compression on several of my dirt bikes. Thanks for the info!👍

[@caseyanderson1297]

Orrr, for fifteen bucks less you could just goto advance and buy one that's built correctly and be ahead. Good video, I was just wondering how far off they really are, because my atv with a fresh top end is reading 110, but should be over 200. Of course, I, like many went with the HF tester... lesson learned..

[@jpegjake]

I suppose there is no reason a guy cant get the taper tap then and avoid using the blue shoe glue.

[@FlyingScot]

Unfortunately the hole is already the width of the valve so you can't taper it.

[@jpegjake]

@@FlyingScot so i assume technically the hole is too large but small enough to get some threads

[@FlyingScot]

@@jpegjake you got it!

[@mikepittenger2299]

Your shrader tool has a core tap. Thanks for the video

[@larryfine4498]

The HF Maddox compression gauge is only 20 bucks more, about the same as your repair costs. Also, not sure I would be sticking homemade gadgetry in the cylinder of a very expensive engine.

[@wtfnetown5049]

What is that 2 stroke twin motorcycle sitting next to your DT? I could only see the exhaust and rims. Love those old 2 strokes!

[@FlyingScot]

That's a 73 Suzuki T500 twin! Just finished restoring a 78 Suzuki TS 100 last week.

[@wtfnetown5049]

@@FlyingScot sweet I had a 76' GT 500. Loved it. I now have a GT 550 and a 71' T250J hustler.

[@davidsherrod6498]

For a few dollars more Pittsburgh pressure checker may be great but by them not having the valve it is junk. I can say this because how many people have relied on this tester and ended end up trashing or rebuilding an engine due to this shortcoming that I’m pretty sure they know about.

[@Pro1er]

Or you could just buy the Maddox compression tester from Harbor Freight for $20 more. If you're on a really tight budget, Amazon sells ones like the H.F. Pittsburgh under a ton of different brand names. There's currently one on Amazon under the Orcish brand name that looks identical to the Pittsburgh kit for $10.99.

[@FlyingScot]

Yeah I found that out later but thought it would be fun to try and figure out how to fix it since I already had one albeit not working .

[@ahenseda]

Thank you so much! You saved the day!!!❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

[@tomcooper748]

True genius ! How did you figure out the correct tap size needed for the Schrader valve you used? and will it be the same for the alternate Lisle and Milton valves you listed ?

[@FlyingScot]

It lists the dimensions for the tap on the wiki page for the Schrader Valve. Should be the same for the Lisle and Milton.

[@thebrokenspokepoco270]

Can you just remove the schrader valve that comes installed in the gauge and just tap the hose and reuse it or does it need to stay installed in the gauge portion and use another schrader valve for this modification to work? Thanks for the information and video.

[@FlyingScot]

That could work. I went to try that but unfortunately my schrader removall tool wasn't long enough to fit inside the neck of the guage

[@boblockerbie7726]

Great video I have a hf and 2 other compression testers that read 30 psi on a new still chainsaw.I've ordered valves and tap to make them right.tyvm

[@gregmccarter2176]

What size tap did you use? I couldn't understand what this man was saying

[@boblockerbie7726]

@@gregmccarter2176 I don’t remember the size but it didn’t work anyway I bought a good one at a auto parts

[@torrinoshepherd7580]

I was about to go crazy. I rebuilt my outboard because of 60/58 reading. Well brand new motor. FU harbor freight

[@FlyingScot]

I feel for you! I had the same issue with my Suzuki t500!

[@arctican7483]

Awesome.

[@pinkwiener23]

Link to the valves isn’t working...

[@FlyingScot]

He must have sold out ..you could use a Lisle 20100 or Milton 1251-2 core replacements instead. These are low opening pressure...I'll update the link. thx

[@pinkwiener23]

@@FlyingScot sounds good! thanks for the reply

[@gregmccarter2176]

I couldn't understand the tap size..or what valve ...my unit is doing the same...