roller ball bearing 850 commando

Hi again:

Just joined yesterday and thanks for the comments
Kommando commented on the driveside layshaft bearing which needs to be a roller not a ball bearing
I believe they changed these to fix the issues with the 750 combat engine ???
Did they also change these bearings on the 1st 850's ( serial number 300000 ) or was it only done to the later Mk's or is there anyway of knowing by serial number ???

Islander

islander said:

Kommando commented on the driveside layshaft bearing which needs to be a roller not a ball bearing
I believe they changed these to fix the issues with the 750 combat engine ???
Did they also change these bearings on the 1st 850's ( serial number 300000 ) or was it only done to the later Mk's or is there anyway of knowing by serial number ???

Click to expand...

Commando main bearings were changed to a special RHP 'Superblend' type roller bearing in late 1972, as premature failure of the standard main bearings had become a serious problem in the tuned Combat engined version that had been introduced at the beginning of '72. RHP Superblend and later, FAG main bearings were fitted to all models from that point (even though the Combat engine models had been discontinued) which appeared to cure the main bearing failure problem.
The FAG main bearings are the type supplied and recommended as the standard replacement for all Commandos.

There is some debate as to exactly when the gearbox layshaft ball bearing was changed over to a roller?
The ball bearing was certainly still being fitted to 1975 850 MkIII models, as members here have said that they have found them in their gearboxes so any 850 MkI or II model would have had a ball bearing originally. There is also a special ball bearing available that some Norton Commando experts prefer to recommend instead of the roller, but generally the roller gives no problems in service.

tks L.A.B.

Tks ever so much for the useful information. I think I was a little bit confused over the different bearings. I really appreciate the reply and you have anwsered my question concerning the main bearings, and will read some more about the layshaft bearings.
Thanks again

Islander

Hi Islander,
Like the main roller bearing (306 E) be sure to fit a special E specification layshaft roller bearing. Roller bearings without E specification are as good (or bad) as the standard ball bearing.

Transmission bearing

Hello Islander,
The tranny layshaft bearing upgrade you are refering to uses a FAG bearing part number NJ203E.TVP2 It can be installed with engine & transmission still in frame. While you are at it, might just as well have lip seals installed for the kickstart and shifter shafts in the tranny cover, and install a clutch rod seal on the other side, all cheap and effective upgrades.

GB

hi islander have a look on norton owners club nsw every ball and roller bearing is listed