1963 Norton Slimline Oil Leaking from Breather

Timed breather jammed open?, check by removing sump plug and blowing through breather while turning engine over.

Hello Sundarraju - you don' say what engine you have - 500,600,650,750 ? but have you checked the pressure relief valve in the timing cover ? The reason I ask which engine you have is because there are two different types depending on the type of timing cover fitted. One type is external at the bottom left-hand side of the cover. The other type is within the cover itself. If the engine has been stood for some time the plunger can seize up through oxidisation. If the breather disc is located properly in the camshaft there isn't much else to cause your problem. Good luck, Howard

Hello There is if the camshaft breather disc spring is not fitted in the right place it should be in betweenthe disc and the cam shaft end when doing a rebuiltengine I alway fit this in first and have the left-hand side looking up Ward and then fit and crankshaftassembly and make sure the cam shaft is on the spring you can feel it when you drop the disc in first and then the spring and then the cam shaft and turn until you feel it mate up with the disc then with your artist brush smearwellseal on to crankcase mating sides and have the ball main bearing fitted to the crankshaft and warm the right-hand side case in the oven and fit over the crank and cam shaft and fit it down until the case has mated with its partnerscase on its two dowels then fit the two bottom screws but do not do them up just yet leavethem slack just give them a few turns to line the cases up and then see if all is free when turning the cam shaft and crank then fit the oil seal washer on the timing side and the small nut and bolt at the front of the cases then stand up right to fit the two nuts on the engine thought studs at the top end of the cases do protect you conrods do not have then banging the side ends of the crankcases this will not do them much good . from here you can then buildup your timing gear well before fitting any top end for this I made out of a nice pace of ply wood and fork to stop the rods moving about it goes over all the studs and fits up to both rods and fit a pace of round Dowling though both gudgeonpin holes to keep things in place now have fun yours anna j

breather sounds OK, a stuck valve in timing cover could be the problem.