1955 Dominator Scavenge problem

Hi .. I have recently purchased a 1955 Dominator 88 ..

It was rebuilt by Tim Bardsley in Canada and has not been run for a couple of years.. After reading the forums I modified my sump plug with a small bolt to ease the wet sump issue. I noticed the oil was a bit sooty, It started easily but there was no oil returning to the tank.
However there was some oil in the sump so I guessed oil (at least some) was getting through the engine. I changed the oil and started it again .. this time ran it for nearly 2 minutes.. at say 1500 - 2000rpm. Still no oil return.
I was unable to see how the oil in the sump gets back to the oil pump.. Should I see a pipe when the sump plug is removed (I don't) .. Is there a oil way that may be gunged up..
Help please.

Thank you

Do you mean you modified your sump plug to look something like this photo.

If yes that will not have caused a problem.

You do not see a pipe when the sump plug is removed.

If you look at the parts diagrams on the Andover site you will see where the oil pump sits. Check the oil pipes are routed correctly from the manual.

Have you drained the oil from the sump and the oil tank and replaced with the full amount? Is there an after market oil filter in the system?

The reason I ask those questions is that the oil can take at least a minute to come through especially if it has to fill a filter.

There are a couple of things you can check. Firstly back off the oil rocker feed on the head when the motor is running. If the oil pump is working oil will come out as soon as you back of the bolt.

Next take off an exhaust rocker cover to see if there is oil circulating up there. You shoukd also have poured about an eggcup of oil down the push rod tube before you started it. This oils the camshaft.

There can sometimes be a problem with the oil seal in the timing over which goes over the end of the crankshaft. It can flip the seal especially if the oil is very cold and the motor reved too high before the oil is warm. You have to remove the timing cover to check this.

There certainly are internal oil ways that can be blocked especially if someone has media blasted any of the parts. But any good mechanic shoukd have checked them all

Thank you for your reply

My sump mod is fairly similar to your image.
Oil pipes are correct to parts diag..
There is no oil filter.
Since my original post I have removed and cleaned the oil tank.. Cleaned the tank mesh filter.. removed and checked the oil pump.
Oil pump very sweet ..
I still can't figure out how the oil gets from the bottom of the crankcase mesh filter up to the pump.. any help with this would be greatly appreciated.
I'm fairly familiar with motorcycle mechanics but this is my first Norton.
Thanks for your help

Where are you located? I could ask John Saywell in Wellington if he could talk the circulation through with you.

Just figured out how to post an image ...

This is my version of your posted image.

Thanks that sounds great.. he could text me on 021448378 I will call him back to save any fees.

I live in Wellington also .. so that will work very well.

OK. I'll ask him. Just so you know he should be OK giving a bit of advice but he is not building engines anymore these days. Retired and working on his own stuff.

OK. He will text you.

Hi John
Thanks for your help.. John contacted me and we had a conversation last night, I learned a great deal.
I'll follow my nose through the oil system and see what I find. I will update when I find the problem.

Best regards

Sounds good. He knows a thing or two about old bikes. Very nice guy.

Hope you find the solution.