Model 50 rebuild questions

Hi Jak (No pun intended)

Most of your fasteners will be Cycle thread (26 TPI) except for the engine casings screwing into Alloy. They are the more course Whitworth thread. (BSW)

If you are not going to auto jumbles, you can buy stainless fasteners online. D Middleton and Andy Molnar have lists of Norton fasteners inc other parts, inc spindles etc.There are others too.

I don't think an air filter was fitted as standard and I don't have one on my own model 50 but I do have an experimental Amal thin air filter I keep trying to find. Will report on it when I do eventually find it.

Lots of people can service your oil pump, inc RGM in Cumbria.

Can't think of any pit falls apart from use Ethanol proof parts in your fuel system if you are not going to run on BP Ultimate. (Not E0 in South West England)

Hi Jak,

There was no air filter as standard, Norton listed one as an option, but I have never seen one, and doubt if anyone else has.

I fitted an Amal 'cake tin' type filter to mine, but I had to heavily modify the oil tank to get it to fit in. ( see pic)

I use Molnars Stainless parts, they are not the cheapest but are always just right.

Re. the oil pump, I think Norvil and RGM will do them, but it is not difficult, all you need is a surface plate (or at a pinch, a piece of heavy PLATE (not sheet) glass ). Mark up and dismantle the pump and lay the pump body face which mates up with the drive side on your surface plate on some oiled 600 grade wet and dry paper (rough side up!), keeping it flat and squareremove a very small amount of metal, then clean and re-assemble with just the gears from that side in (the feed gears are narrower than the scavenge, don't mix them up). Repeat this until you feel just the tiniest amount of drag, the side float is now gone, now do the same with the other side. Fully reassemble the pump, which must be free to turn dry, if it tightens a little, face off the end plates the same way, but otherwise leave them alone. The pump bodies for the singles are die-cast, so do not go at it like a mad thing, be patient and you will have a good pump with minimal leak-back.

If you don't fancy doing this, as I said I believe Norvil etc will do them.

Good luck, they are great bikes,

Cheers,

Niall

Good luck, jack. I'm a big believer in powder coating but I know that's not for everyone.

My model 50 doesn't wet sump but my 500cc version does. It will help to slow down wet sumping if you leave the engine on compression and then if you can get a decent ride in once a month that might suffice. On the other hand, if you plan on laying the bike up over the winter just allow the sump to fill but put a drip tray under it.

Hope you found some stainless fasteners and don't forget that stainless rims and spokes are not a bad idea either.

Have a go at refurbing the oil pump yourself!

It is very easy to dismantle, and if you get a piece of glass and some grinding paste, you can give your pump a new lease of life for next to no money at all!