Hi guys On my 1975 Norton 850 MK111 about 200 mi ago I replaced the clutch with factory parts new clutch disks, plates, hub, and clutch cable all at the same time. but the other day I got on it little in 3rd gear from a low rpm and felt the clutch slip a little do you think I should have replaced the spring/pressure plate at the same time maybe it just doesent have enough pressure any more or any suggestions on what it could be.
The usual cause for slipping with the 850 bronze plates is oil migrating from the gearbox. As the bushings wear the seepage can get worse. So depending on the amount of seepage from the gearbox, the clutch plates can be contaminated pretty quickly. The fiber plates seem to be somewhat less susceptible to this.
Cleaning is ok - do it and empty your primary. Refill prim with SAE 20 type oil (thinner). I use (as many of this board) oil for automatic gear boxes/cases... (Roy Bacon already in the eighties, stated in one of his books "Norton Big Twin Restoration" the need for a thinner oil in primary. A formal deviation from spec so to say). And put in just below the level mark (the lowest and smallest cap on your primary case).
Said actions prevent drag too.
'73 Commando Basket - new aluminium cyl '93 Ducati 900 SS
"Better lit a light than cursing the darkness" (Confucius)
THE MARK3 BLUES....If you still have bronze plates get rid of them. I went through the clean the plates every 200 miles for years...a pain in the ***. I am useing Barnett friction plates now which seem to stop the slipping. you will still have to clean them once in a while to stop clutch drag. Daves clutch rod seal is also a must. Use automatic transmission fluid in your chain case and put your bike on it's sidestand when you fill to the plug.
Re: Clutch Slipping ?#75704 08/18/081:20 am08/18/081:20 am
I just replaced the stock 850 bronze plates with Barnetts and got the stack just right. No slippage and a 2 finger affair. I also use this set up on a 750 and run it dry with excellent results. I use type f trans. oil in the 850