Ive just fitted a new Primary case seal to my 1949 ES2, cut to size as instructed and not overtightened the outer case either, Still leaks !!! Is this a common feature to these singles that I will just have to live with ?
Well, yes actually. I'm sure there'll be plenty of members who have their own solution to getting the primary oil tight, but if there wasn't an issue there wouldn't be so many suggestions. The question is how bad is it? If it loses all its oil on a 30 mile run, I'd say you need to keep trying to make it better. Certainly try to make certain that the band isn't getting twisted or distorted as you push the cover on, a smear of grease should help that. Alternatively, fit an expensive belt drive with a sealed release bearing that runs dry so won't EVER leak!
You will have to be very methodical if you want to sort this problem out. Make sure the cover edge does not come into contact with anything that will stop it fitting properly. check the faces of inner and outer are smooth and not bent ,check the seal on the gearbox shaft.Check the innercase seals against the crankcase. Use the minimum amount of oil. Buy a 500g tin of RED RUBBER grease and use it. Are you sure its not the engine breather that kicking out oil? or the gearbox.
Im sure its the chain case as I i took it all apart, cleaned it and left it for a few days. when I refitted and topped up with oil there is now a drip under it ( dripping off the inner chain case lower mounting bracket. When I put on the new seal it was super tight getting the outer chain case over the new seal ( I did lubricate it to help it slip over. I have read other people have had leaks and I guess its common. Don't really want to strip it all again if I can't cure it.
its just a drip where it stands on my bike ramp, its not really bad. Don't want to fit a belt drive as I want to keep it original. Guess Ill have to live with it.
The bottom bracket where you say the oil is dripping off, is riveted to the inner case and this can come loose and chatter with vibration. This then enlarges the rivet holes and lets the oil leak through. To check if this might be the problem, undo the nut that secures it to the bottom gearbox bolt, you can then see if it is loose. Also it is possible that either chain can wear through the strengthening webs on the inner case, but you will have to strip all the primary side off to be sure.
The bracket must not pull or push the case as it will distort it. If necessary use a packing washer to adjust the fit.A drip or two after riding is pretty normal ,it should not leak if just standing.
Ive checked the lower bracket and as you said it moves so the rivets are loose I guess .
Im guessing long term I will need to strip it out and re rivets it.
If the leak is not too bad, its not worth disturbing everything until you need to. You will know when it's time when you feel embarrassed about the mess it leaves when you are parked up in public !! Just check and top-up before any long journeys or after a couple of weeks or so.
Stick some Hylomar on the seal before assembly....simples
There is the theory that the sticker on the primary cover was misprinted by the factory and should have read “Patented Norton Oil Leak”.