Fitting the Morgo Oil Pump         

Early on in this build I decided to fit a Morgo high performance oil pump to the Squariel. The Morgo rotary oil pump is a direct replacement for the original unit albeit with significantly increased capacity. It provides so much additional oil flow that it is recommended to fit a larger size oil return line if the bike is to be used on long distance, high speed work. My machine is unlikely to be doing either of those duties so I will stick with the original pipe for now.

Changing the pump was a simple matter of removing the worm drive nut from the camshaft. Remembering that it is left hand thread of course! Then replace the nut with a new drive nut supplied in the kit. There are also some shims in kit. These are required for setting the gap between the camshaft drive and the oil pump drive face. This gap is set at between 0.005” and 0.010”.

Morgo oil pump Square Four Ariel
Heart Transplant courtesy of Morgo

There are three mounting bolts supplied in the kit also. These were too long for the mounting holes and had to be shorted by 4mm each. Morgo says that this is by design as Ariel threads were never uniform so it is up to the owner to work out the correct length.

Ariel Square Four MKII bottom end assembly and engine stand
Ariel Square Four is starting to look both square and four!

It is another job “almost” finished. I need to fit the timing chain at this stage to complete the oil pump change over. However, I am unable to fit the timing chain as I need to set the camshaft and crankshaft timing. To do these, I need the barrel fitted. To do this, I need pistons. And so it goes on! In good news, I have ordered replacement pistons now. The mores measured at the outer limits of standard. This was great news. I have decided to fit +0.20” pistons. The reason for this that rather than being at the limit of wear and fitting new pistons, I am better to have the cylinders rebored so that they are round and parallel. This gives the engine the best start in life possible. Along with my Morgo high performance oil pump of course!

Back to the 12V Conversion        

The path to completing a restoration is never a straight one. I had decided a while back to keep the bike as stock as possible. This comes with concessions for changes that can be easily reversed and will add to safety and enjoyment of riding the machine. A late change was the decision to move from 6V positive earth to 12V negative earth. This was as simple as changing the positive earth voltage regulator for a negative earth one. I am using an electronic regulator so the conversion between 6v and 12v is a simple wiring change. Dragonfly Motorcycles happily exchanged the positive earth one that I had for the price of postage. Of course, this led to another order of miscellaneous parts but hey, it always does!

Smiths Chrono Electric

The motivation behind the change is the Smiths Chronometric speedometer fitted to the Ariel. A lovely gauge which works well. Aside from two small issues that is. First is that it is in MPH. The second issues is that they are not super accurate. Neither are big issues in isolation. However coupled with a local police force not known for its leniency and the prospect of maneuvering a large motorcycle with “optimistic” braking retardation, I want to make riding it as stress free as possible. Enter the Smiths Chronoelectric speedo. I purchased mine from Norton Race Parts. They also supply an electronic drive that fits to the gearbox. There were not able to tell me if it would fit the Ariel so I took a punt anyway.

Smiths Chronoelectric GPS speedometer
Smiths Chrono Electric modern take on a traditional classic

It turns out that it “almost” fits. A bit like “almost” finished! The Burman GB gearbox has a tongue drive while the cable fitted has a square drive. I had a spare drive so with a bit of experimentation, I have been able to make it fit. I will not know for sure until I get the bike on the road but for now I am happy. If all else fails, I will get a separate GPS unit to drive the speedo.

Smiths Chrono Electric speedometer drive
Of course it will fit!

Next Steps

If the pistons arrive before the end of November, I have a good chance of getting the barrels on by Christmas. I could not ask for a better Christmas present than that!