1949 ES2 500 Primary sealing Gasket

I can't find the right gasket for this bike. All are to thick and the primary cover won't go on. It needs to be about 3/16" or 1/4" thick. Width is ok at 7/8". Ones I'm finding are 3/8" thick. Any ideas? Part I just received is 06-7627. It is way to thick. When I say thick I'm talking about height I guess not how wide it is on the inner primary lip.

Thinking I need the 5/8" x 3/8"??? Any help??

captwk said:

When I say thick I'm talking about height

Click to expand...

Now we are confused !

The tin cases have a slight taper to them, so when you lay the giant rubber band out on the faces,
they press together so the rubber band is sandwiched between the tin covers.
Large lashings of silastic may be necessary to get it to seal...

I still remember I bought a NOS ex-army one, and when it arrived it was curled up and like a rock.
I mentioned this to the seller, some time later, and he said didn't you soak it in brake fluid (heavy alcohol),
they soften right up and can be fitted to anything.

I have a good one stashed away some place, could measure it if it would be helpful.
But that soaking in brake fluid is the trick.
(if modern ones are up to it !).

Just had a quick look - the new one here is about 7/8" wide, and 3/8 thick.
I'm not aware they came in any other size ?
If the cases have been bent or overtightened and distorted, fit can be a problem...

The outer cover should go over the gasket. It may not seat fully inboard with the inner cover, but if you can get one or two threads showing after the big nut is threaded on, that should be good enough. In fact, one should NOT tighten the nut more than two threads exposed. Tap the outer cover all around with a rubber mallet to help set it home.

I use silicone to bond the gasket to the inner cover, then a smear of silicone around the bottom half of the outer cover flange, and a large bead of silicone on the edge (the 3/8 way) of the gasket, with a corresponding bead on the shoulder of the outer cover that mates up to the gasket edge. So far, this technique has been leak free. The outer cover will come off when necessary, despite all that silicone.

Good luck and let us know how it comes out.

Slick

I did find one that measures 5/8" by 3/8". Now that you explained how the fit should be I'm thinking I need the 5/8" x 3/8". Previous owner ground the old 7/8" x 3/8" gasket edges to a taper. Then forced the outer cover over the gasket. But the edges are not even so it leaked. Then used 3m adhesive. Not knowing what was right to start with had me confused. Thanks for the input.

Personally I never had a problem with my 59ish ES2 primary CHAIN case gasket ONCE I bought a new one and realised the reason the lump leaked was because the original gasket had compressed so much it was not sealing correctly. It is worth looking at the original patent drawings to note how it was DESIGNED to seal. I suspect many owners in an effort to cure their leaking chain cases followed the advice given by idiots and played at being unskilled metal bashers ending up totally knackering the outer cover. The section on the design and development of the Noreton pressed steel chain case given in The Norton Story published in Motor Cycle Sport decades ago is worth reading. The relevent part is contained in the January 1972 issue on page 37......

'The pressed steel chain case was Auther Carroll's basic idea developed with much blood , toil and sweat by myself.As you can imagine, the pressing had to be absolutely right to ensure a good oil seal.Tool wear had to be watched closely and variations in the temper of the steel was enough to upset things. Ferodo developed a special clutch insert material to run in oilbut even so we had to fit a band around the outside of the clutch and control the amount of oil the chain case would holdby the position of the filler plug'.

The clutch was NOT designed to be employed with oil on the friction interfaces but designed as a DRY clutch that would not slip when maximum torque was shoved through it. With oil on the friction interfaces slip occurs which is why the manuals state that one cause for clutch slip can be OIL ON PLATES and the cure given is to strip the clutch and wash the plates in petrol. Funny how so few Norton owners read manuals..... Other people were also involved with the pressed steel oil bath chain case development , people such as Mr Phil Heath who told me that the CORRECT oil to use was straight SAE10 or 20 and the correct level was such that oil just touched the bottom of the chain so as to give oil mist lubrication for the chain. Mr Heath made the comment to me that it did very little for chain life.......CORRECT lubrication for a chain running at the linear speeds we employ would be sump and pump.......but I guess oil mist was better than mud water stones and human flesh asnd bones!!! incidentally Gold Star chain case fillling instructions is till oil can be seen to be just touching the chain....Gold Star clutches also being designed to be run DRY.
Wonder how many chain case outers have over the yearsbeen subjected to having people play with them and buggering them up ????? Many years ago I saw several BIG steel containers full of new chain case pressings ...the factory owner refused to finish them for us stating that he had lost so much money when AMC closed their Birmingham Norton factory he would see them in the scrap rather than finish them.