- Single row ball bearing. Fitted to all pushrod and sidevalve engines (from 1930's to late 1950's). These are original high quality RHP bearings (plastic sealed)- but are in a 'standard' fit, not the original looser C3 fit. Feb 19: Read detail lisitng for update
Update Feb 2019: We do sell the correct C3 fit version of this bearing, which Norton originally fitted - that is Item 0242, but stocks of that bearing are extremely limited, and if sold out, or you feel comfortable to fit the standard fit type listed here (which is slightly cheaper), then this is still the high quality RHP brand and still an excellent bearing.
Just like the even harder to find 'C3' version of this bearing - these bearings are now obsolete and very difficult to find, I only have a few of these left and once they are gone am not sure if I will be able to obtain more.
Fitting a 'non C3' bearing just means you need to be a little bit more careful when running the bike in, to let them wear in first - so to avoid the bearing spinning in the crankcase bearing housing. If you think you have a crankcase where the bearing may have previously spun in the housing (and the alloy bearing housing looks slightly grey or worn) - then I would advise paying the extra money and going for the C3 fit listing - Item 0233 - while they are still available.
Final point on ball and roller main bearings fitted to 1930's/50's OHV and SV engines: Unusually, Norton's showed a roller bearing being fitted on both sides of the crankcases on OHV/SV engines (i.e. 1948 catalog), with a ball bearing fitted just on the outer drive side. However, I have stripped OHV engines down in the past where a ball bearing is fitted both sides, with just the drive side inner being a roller bearing. Not sure if it makes a great deal of difference - as like the SOHC engine, the OHV/SV engine was locked to the timing side bearing - but worth noting if you are struggling to find two roller bearings