Triumph Lubrication System Test Set By Dunleer

Triumph Lubrication System Test Set By Dunleer

I Monitoring and checking oil pressure is a task that is often failed by mechanics and engine builders alike. 

An engine plays a similar role to a humans body.

The primary blood line in your motor is the oil, and an oil pump functions just like your heart.. if one (or both) where to fail it would be catastrophic, unless you catch it just in time.

Today I would like to share a unique piece of Triumph history that served a purpose then, and also serves a purpose in my workshop today.


The GT703 / JT763 Gauge


Dunleer Oil Pressure & Scavenge Gauge For Triumph

The Dunleer lubrication set sports (2) large gauges that are easy to read and also very accurate

The JT763 / GT703 lubrication system test set was manufactured here in the USA by Dunleer and was produced expressly for Triumph.

This rare piece allowed the user (or mechanic) to check an engines oil pressure and also perform a scavenge test.

Oil pressure and return scavenge are the two main key factors to achieving a reliable lubrication system.



From my research, I have not been able to find any documents online in reference to the manufacture "Dunleer".

It is unknown to me if Dunleer was a company that specialized in making universal gauges or perhaps tools for the automotive industry..

(If you have any additional info on the Dunleer company, please let us know in the comment section below)


How it works

The sole purpose of this unit was to allow mechanics to achieve the following:

  • Obtain engine oil pressure
  • Measure scavenge suction


Oil pressure


Oil Pressure Switch Fitting


When checking an engines oil pressure you simply use the provided adapter that comes with the unit and install it in your timing cover or engine case (depending on model).

You may have to remove your existing blanking plug or switch prior to using the gauge 

There where different adapters supplied separately for singles, twins and triples while using the same gauge 

This unit shown above appears to have the "twins" adapter which features a “tapered thread” for Triumph and BSA models up to approx 1974.

Most Triumph and BSA motorcycles from 1969 and on had an auxiliary to accept an oil pressure sending unit (warning light) which in return could allow an oil pressure gauge to be fitted.

Although most Triumph twins had a blanking plug on the timing cover prior to 1969, one could remove the plug and fit an oil pressure gauge.



 The purpose of checking and measuring the scavenge is to get a reading of how much "suction" the oil pump is creating when moving oil from the sump back to the oil tank (return)

A weak pump or a leak around the scavenge  pipe (inside your case) can cause a week return suction which in return can also cause wet sumping.

To check the scavenge suction, take the provided hose end and install it over your scavenge pipe inside your engine.

 Checking the scavenge can only be done while the motorcycle is running for a short period of time - it can get messy!

Service Bulletin

Triumph Dunleer Oil Gauge Service Bulletin 3-1973

Triumph service bulletin showcasing "Dunleer Lubrication System Test Set" (click on image to enlarge)

Searching through my book of original Triumph service bulletins I stumbled across this Triumph service bulletin dated 7-27-1973.

 The Triumph service bulletin showcases and describes a new lubrication testing rig that was available (and recommended) for dealers

The image of the unit is confusing as it shows a "JT-763" model while they list a "GT-703" model?

My gauge happens to be the "JT-763" gauge as shown in the photo, however, I have seen this type of gauge in various styles including some with a "Triumph"logo reading "made expressly for Triumph".

Despite the different gauge types, they will all perform the same tests.

Modern Gauges

Oil Pressure GaugeCBS exclusive - Triumph / BSA handlebar mount oil pressure gauges

If this original Triumph gauge and blog post has inspired you to check your oil pressure we do happen to stock a similar unit that will allow you to measure your engines oil pressure while your riding your motorcycle 

There are some limitations on oil pressure gauges that can be fitted to older Triumph, BSA and Norton motorcycles especially on early models..

Click here for more info or to purchase your own oil pressure gauge today

Thanks for reading

Thanks for taking the time today to read our new blog post.

Should you have any questions or would like to join in on the conversation, please feel free to drop us a comment in the section below 

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Ride safe! - CBS

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