Shifter Shaft Leak

Hi Guys, my 74 mk2a started leaking from the shifter shaft. Its on the right hand side of the bike. Is the seal accessed from outside the cover? Any guidance is appreciated.

Inside. There are two O rings on the ratchet assembly shafts. Remove the Outer Cover and the two bolts holding it in place. There is a small one on the ratchet spindle and a larger one on the pawl carrier

Thanks. I only see one o ring in the parts diagrams though.

number 6 in this diagram
https://andover-norton.co.uk/en/shop-drawing/209/gearbox-inner-cover
and number 40 here
https://andover-norton.co.uk/en/shop-drawing/208/gearbox-outer-cover-kickstart-gearshift-lever

the first link O ring almost never gives an issue. it is the O ring in second link where the issue is. the bushing does not have a tight enough fit and it allows the shaft to vibrate. that vibration makes the shaft act as an oil pump and forces oil past the O ring. you can find an X ring at most hydraulic shops or look for a shop to convert it to a MKIII seal but even than the fit of the bushing is critical.

Got it. Is the replacement pretty straight forward or are there some particular precautions to take along the way? Should i check/replace other items as long as i have the cover off? The bike sat for 35 years. We (my son and I) aquired it last fall and fixed it up and got it running over the winter. We did not take the engine or gearbox apart. May do some of that this winter but we have put 600 miles on it and the gearbox seems to be functioning ok.

Very straight forward. Both o-rings can be replaced easily with the outer cover off. The 04.0006 is supplied as an X ring now, which seals better than the O- style. Old Britts has them - get a new outer cover gasket too while you're at it.