Ariel Owners Motorcycle Club

Hi Guy,s
Information required on oil circulation.
Is there a recommended procedure to ensure oil circulation before the initial start up of a newly re-built NH engine.
Many thanks
Terry

Hi Terry,
When I rebuilt my VH engine I squirted lots of oil into the crankcases down the conrod onto the bigend made up a oil pipe to the flow side and turned over the engine to prime the pump, reconnect the pipes fill up tank and oil every where you can top of piston, rocker spindles etc., and the pump soon picked up the oil in the crankcase,
As long as there is lots of oil at the start and in the rebuild there should not be a problem its surprising how quick the oil gets round the pump does not seem to pump much when worked by hand but as soon as you start it it soon works well but it might smoke a bit when it does start up and keep the oil cap off to check for the return oil which might take a short while to come through in short spurts. Best of luck Clive. anybody else got any tips.

Take the oil pump off and make sure it works by putting oil in the top 2 holes and depressing the plungers. A working pump will shoot the oil into your eyes so wear protective goggles when you do this.

Put the pump back on the engine and fill the oil tank. Slacken the two screws which secure the pump to the timing case and wait until oil flows out from behind the pump before re-tightening the two pump screws.

Make sure you have oil in the crankcases to splash about and save the engine if something doesn't work.

Start the engine.

Thanks guy,s for the replies. It now gives me confidence that I will not do anything stupid to mess up the engine. I will report back sometime in the future on how everything went.
regards
Terry

I always kick the engine over (spark plug out, or using the decompressor) until I see oil returning into the oil tank.

SG

Earth the lead if you take the Plug out. The Magneto doesn't like an open circuit. On singles I put oil in the Motor. About 1/2 half a cup plus a bit in the Ex rocker box and that will oil the cams and the rest till you check the flow. Paul J has covered it well. Pays to replace the Balls also They can wear oval and seal less reliably. They are a Funny size. Some one will know what it is. Nev

Simon.Gardiner wrote: Sat Jan 17, 2026 3:13 pm I always kick the engine over (spark plug out, or using the decompressor) until I see oil returning into the oil tank.

SG

Yes I follow exact the same procedure… just kick over untill the oil returns. (spark plug out, making sure it makes contact with the frame)

Hi Guy's,
More help needed on my oi[ circulation problem.
I have carried out all that was suggested but still can't get any oil to get back to the tank or rocker feed. I daily pump oil down the rocker oil feed pipe and I have put oil down the pushrod tubes but no joy. I have been regularly kicking the bike over daily but nothing comes out into the oil tank or out of the rocker oil feed pipe. What have I done wrong?
Have I connected the feed from the tank to crankcase wrong?
The rear take off tube on the tank which is the return I think ) is the nearest to the frame) I connected to the lower pipe take off on the crankcase. The front pipe on the oil tank which is the feed is connected to the upper pipe on the crankcase. Is this correct?
If I start the bike up before the oil comes through will there be any damage. Bythe way the oil pump has been re-built and primed and replaced with the gasket behind it in the correct position.
Hoping for a solution on this
Many thanks
T

I wouln't start the engine on a 'hope' that the oil is circulating.

How long will you run the engine for until you decide thats enough ?

Just a thought but, when you built the engine, did you put the extra little circular paper gasket on the copper oil return pipe inside the cam chest? If this gasket is omitted then air leaks into the "suck" side of the return pump and it won't draw oil up from the sump to the pump.