Many people make the mistake of assuming that "new" is better than "used".
There are many oil pumps available for Triumph twins, but please be aware that there are some very low quality pumps on the market today. The pumps in question can easily be identified by having slots on the body where it meets the engine case versus the drilled holes on the originals.
We have come across these pumps installed in customer's engines and have found them to be the source of both wet sumping and low oil pressure.
The check balls did not fully seal because the seat surface was too rough and out of shape. On one pump the check balls were not even round! In both instances it looked like the tooling used to make the pump was worn out, or never sharp in the first place. One of these pumps was Made In Taiwan, the other was "English Made"...Surprisingly they looked exactly the same with the same poor quality.
WHY YOU SHOULD CARE
An oil pump is one of the most important parts in an engine. Without oil circulation, heat will build up and bearing failure will often follow. Sometimes an old original oil pump is better than a new poorly made one. Don't trust any pump besides Morgo without inspecting the check balls and seats. It is bad economy to buy a "cheap" product that may cause a lot of expensive damage down the road.
MORGO OIL PUMPS AND REBUILD KITS
Autovalues Engineering manufactures Morgo oil pumps in England to very precision tolerances. Franz and Grubb Engine only sells these as they are the highest quality Triumph pumps ever made. Do your engine a favor and install a Morgo pump. Available for 500, 650, and 750 Triumph Unit and 500 and 650 Pre Unit twins. A 20% increase in oil flow over the stock Pre Unit, increased scavenge ability, and superior materials and machining, make this oil pump the choice for Triumph restorers, racers, and enthusiasts worldwide.
REBUILD KIT
Also available is a plunger pump rebuild kit consisting of two check balls, two springs, and two nuts. Rebuild your old pump for a fraction of a new one.
SUPER ROTARY PUMP
The Morgo Super Rotary Pump is a modern and patented design intended for high performance applications. Entirely designed and made in the UK by Morgo, this pump has been proven since its introduction over twenty years ago. This pump will fit all 350, 500, 650, and 750 Unit construction Triumph twins. Also available for Pre Unit engines.
Pumping more oil means more oil flow and better cooling. You will still have to consider modifying the Pressure Release Valve (PRV) and be sure to prime the pump after installation, oil changes, or removal. A pdf file of the instructions are on each product page to help you decide if the rotary pump is right for you.
IN CONCLUSION
Factory Triumph oil pumps generally work, and many are still in use today in engines around the world. The plunger oil pump is a simple yet stout design and can work in all kinds of difficult situations. However, not all aftermarket parts are of the same quality. If you do inspect your pump seats it is suggested to hold the pump body between two soft pieces of wood in a vise. This will prevent body distortion.
If the chrome on your headlight is not high quality it won't affect much. If the seats on your oil pump are machined badly, a lot of wasted time and possible engine damage can occur. Don't take chances with such an important part of your engine.