1. 8. Screw the Pro-Gauge into the adapter to a good tight fit.  Wipe of any finger prints or oil and thats it.  The  Pro-Gauge is installed.


Try the Pro-Gauge

out for yourself, we are confidant that you will be extremely satisfied with the precision and durability of

this gauge!  Our Pro-Gauge comes with a one year warranty.

Contact us:

Ph  1-765-564-3946


Monitor the Oil Pressure

on your Harley-Davidson motorcycle with confidence.

The Pro-Gauge is an oil pressure gauge designed specifically for the harsh environment encountered by the air cooled engine.

This High Quality Gauge

has an 1 1/2” stainless steel case, 1/8” npt threads, a glass lens, is liquid filled and has an easy to read white dial face. Not only is it tough, it is sure to enhance the beauty of your Harley!


PG-1  Pro-Gauge

Use on all


Knuckle, Pan, Shovel and Evo Engines




PG-1T  Pro-Gauge

Gauge and Tappet Adapter

Use on all

Evo, Shovel and Pan

Harley-Davidson Engines



Tappet Adapter

Use on all


Pan, Shovel and Evo Engines


$ 20.00

$ 30.95

$ 50.95


Replacement Cap

Stainless Steel Hexed Caps

Replaces the tappet screen, check valve and

pressure relief caps

(1948-1999 Harleys)


$ 10.00 per cap

e.r.t. products, inc.

Gauge and Tappet Adapter Installation


  1. 1. The tappet screen plug is located directly behind and to the right of the rear tappet block. This plug is made of steel and has a straight screwdriver slot in it.


  1. 2. Once the plug is removed you will find a spring and the tappet screen. 


  1. 3. Remove the spring and tappet screen, clean both and check for any damage. Once cleaned, reinstall the screen first and then the spring.


  1. 4. Unscrew the tappet adapter into two pieces.  Take the bottom half and install it into the tappet screen hole.


  1. 5. Snugly screw the bottom adapter down to a tight fit.


  1. 6. Apply teflon tape to the threads of the  top half of the adapter.  Install back into the bottom half of the adapter.


  1. 7. Tighten and align the top of the adapter to face towards the rider as shown.


~ Scroll Down To Find ~

  1. BulletGauge Info

  1. PRO-JUSTPurchase the Pro-Gauge

  1. shapeimage_34_link_0Gauge Installation

At E.R.T. We Stand Behind Our Products - Your Satisfaction is Guaranteed or your Money Back !

~ Do Not Install On The Oil Pump ~

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Harley-Davidson Oil Pressure Specs 1940 to 1999 Engines

Cold engine start-up:  around 44 psi.

Warm engine at 55 mph and up:  30 to 36 psi.

Warm engine At idle:  at least 10 psi.