Primary to Belt & Clutch Questions - 74 850

Hello All,

I'm new to this group and kind of new to Nortons. (owned one for about 2 years) I have a 74 850 Interstate with 9500 original miles and a very cherry bike. I took the bike out today and the clutch was slipping fairly consistantly. I hate vehicles that leak so I was already considering going to a belt drive system, so now I'm thinking the time is right to do both the clutch and the belt changeover. Looking for advise re. the following:

1. What belt conversion kits are recommended? I sent several notes to one guy on the web that appears to build them out of his home shop but never received a response so he must be doing so well that he doesn't want or need my money. That being said..... he's out of the running.

2. What clutch is recommended for a stock motor with a belt system? A stock 850 clutch or something else? I hear the Barnett set-ups are 'grabby' so I don't one of those unless there's a trick to eliminate that 'grabbiness' with the use of different plates, etc.

3. I haven't opened the book yet to see if any special tools are needed to perform the changes. (especially the clutch change) What special tools are needed to perform these two changes? (primary belt conversion & clutch change/replacement)

4. An 'expert' I met insisted that if I convert to a belt system and eliminate the ATF in the primary, then I have to install a sealed bearing on the clutch basket. Is this true or false for the 850 commando?

5. I've seen a few threads online that state that you have to vent the primary if you convert to a belt system. Is this true or false?

Thanks for the help as I hate to re-invent the wheel and I'm sure many of you have already dealt with these topics first hand!


Doug Gale

http://www.trackmasters-racing.com

1. Maney
2. Barnett is fine
3. Clutch compressor
4. Sealed bearing will come with the Maney kit. Be aware the that you may need to replace the clutch center too.
5. False

Hi Doug
I have both a Clubman Racing belt and a Maney.
The clubman was the cheaper option. Duties and Brokerage fee put the maney over the top for me. That’s the way the cookie crumbled here in Canada. I asked Steve to send via Royal Mail but as most have turned to use of couriers for convenience, (this is where the added costs come from). Surflex Clutches are nice and punt the bronze plates if you have them in your setup now. You might need to replace the center hub if its notched via (bronze friction plates). Sealed bearings come with both but need circlip for center hub or use your old one on your chain drive. Good to get a Dynodave clutch seal to stop gear oil from migrating into clutch thru shaft.
Tools Clutch compressor. Blue Loctite, new clutch location circlip or use item 15 on Mk 3 e start by checking this thread:
gearbox-mainshaft-circlip-t13955.html
Stack height is important and you may wish to purchase an extra steel plate. This made the difference between a three-finger clutch pull to a single finger pull with no slip.
Again check your clutch center hub. If at all notched get new.
Cheers,
Tom
CNN

Nortiboy said:

dgale914 said:

" I took the bike out today and the clutch was slipping fairly consistantly. "

The only reason a Commando clutch slips is the gearbox oil chases the clutch push rod and contaminates the plates with really slippery oil.

A Dyno Dave clutch seal, give the plates a good clean and you will have no slip clutch.

Click to expand...

Click to expand...

+1 on the above.
I've put 5,000 miles on a DynoDave clutch seal, the previously dragging clutch now continues to function perfectly, also not a single drop from my primary, sealed with RTV on the o-ring and filled with ATF. Read this first: http://atlanticgreen.com/ndnsclutch.htm and this: http://atlanticgreen.com/ndnsclutch.htm

I'm not saying the belt drives aren't cool, but the old fashioned chain and sprocket works very well with a couple simple tweeks.

Hey Guys,

Thanks for the info and insight on the various issues and options for the clutch and belt drive. I haven't had any clutch issues with the bike since I've owned it and noticed no slippage the last time I rode the bike around Lake Tahoe last month. However, I do know that between that ride and yesterday's ride the only difference was that the bike has been sitting on the side stand for a month. I typically have it on the center stand. I wonder if that angle promoted the flow/leakage of gearbox oil into the clutch via the clutch rod? Hmmmmm????

Anyway, I'll crack this open next week and see what's going on inside. I also have a lot of chain noise after a longer ride when everything is nice and hot so I'll have to check the tension, etc. Today is car day so I'll be tuning on my Tri-power L71 67 427 Corvette 'beast' car. 'Honey do' list after that! :shock:

Thanks again guys!

Doug Gale
http://www.trackmasters-racing.com

Pretty normal to have to clean clutch plates every year. And a lot cheaper than a belt drive.