Nice Bike. I have a 64 Atlas Café Racer that I've owned since the 1970s and a 63 650ss completely concours standard.. Noàw the clutch. Yes I use Automatic Transmission fluid. Either age or the ATF rots the Rubber bushes, replace every 5 years. Above all realise that what looks like the chaincase drain plug is the Level plug. You put the bike on the centre stand top up the ATF then open the plug and let it drain to level it shoulod carry VERY little fluid. With that and centrifugal force that clutch runs virtualy dry. It should not slip, was used on many drag bikes back then. The cam on your 650 is the "SS" cam. That was the production racing cam of the period and won multiple Thruxton 500 mile races. In it's day the 650SS was road tested at 119MPH yes that was 10MPH faster than the Bonneville of the same year. If the engine is right and you screw the nuts off it it will do 120MPH. If you really worry about stress fracture, fit late Commando rods, but they are heavier, you will need to rebalance the crank. Norvil will fix all that. The sidestand is a horrible bodged add on. On my Café racer I tool a P11 sidestand and had it braised on nicely so it did not crush the frame tube. ENJOY
Yes, the 650 SS has a hot cam. It was called the sports special grind and it was used Manxman twin and a few other limited-production sports bikes. It was carried over to the Atlas when the Atlas was upgraded to twin mono-bloc carburetors and the same cam was used on the Commando models from intro up to the electric start 850 MkIII (also, the Commando Combat engine used a different cam grind). The SS cam grind was considered one of the best back in the day and it provided good performance for many Norton twins.
Hi mate, interesting about the cush rubber thing. I’ve got one of these, getting a bit of clutch slip, also using ATF. I’ll look at it in the winter. I used Commando rods when I did the engine so not too worried about them, I’m more scared of the wheels falling off or something 🤣. Also, looked into a Quaife 5 speed, and seem to remember more like £3000. For 1300 or 1500 I might go for it, but don’t need more speed really.
Hi , I've just noticed your recent reply and I've also recently bought a 650ss I removed the primary chain case to check alls well , then found the sealing band was too big to go back on by 1½ inch (expanded ?) , so I bought a new one from a Norton specialist then found that was too thick , eventually , carefully linished the band thinner , now to see if it's oil tight 😏 ,,,, have you had any annoying events like this ?
ATF is the best for Commando primary chain cases too, but you've got to be careful on both bikes to make sure you use bog-standard ATF and nothing more modern because modern automatic transmission fluids can contain a friction reducing element that can make clutches slip (on all Dominator models, but most especially on Commandos with their diaphragm clutch..) - The 5 speed gear box is/was by Quaife, I'm not certain but I think it has to have a special gearbox shell too ?.. Be careful if you're offered a Quaife gear cluster second-hand because the initial versions were for racing only and had no provision for a kickstart, later there were both race and road versions. By the way.. 'Quickshift' = Idleness.. 'ABS' and 'Rider Modes' = Papering over your lack of experience and talent !..
The bike rides sweet by the looks of things in the vid :-) Is cool you sorted the clutch issue, is the cush drive in the clutch in place instead of having one on the rear wheel? 110mph is not to be sneezed at, nice! :D
Thanks mate yes Cush drive is in the clutch nothing on the back wheel they didn’t really do it that way back then most had a big spring on the end of the crank with lobes on the drive sprocket and on a small collar with lobes on and was held together with a spring and big nut it did the job quite well but they started fitting alternators in that position so had to come up with a different design
