Why does my clutch slip?

Status
Not open for further replies.
Pull the clutch apart, inspect all items. If you don't know what to look for take pictures and post them. Stack height is not dependent anything but stack height, doesn't matter what parts or where you got them from. Don't assume anything.

And post pictures of the clutch center. It should be well notched and ready to be replaced.

Once you get it right you will be amazed.
 
Hi Staytite
No i did not fit a new diaphragm and the only reason was the bike had only done 13.000 miles. But it is important to get the stack height correct. I just fill the basket so i can just get the diaphragm and cir clip in and that gives a nice light clutch. 14 lbs pull at the ball end of the handle bar lever with a spring balance.

Cheers
ELLIS
 
Belt drive makes everything good.

But I have found that I have to drill holes through the teeth in the large drum to allow dirt/debris to escape.
 
ashman said:
Yer its a freak my Norton amazes me as well and my mate who got me into Nortons and Featherbed frames can't believe it, he went the other way building Tritons, in his own words Triumphs are more reliable lol, he eats his own words everytime he comes around.
Yes they do eat the clutch centres and I only replaced the orginal one 7 years ago, not sure how long the one I replaced with will last, mine you it was pretty flogged out when I replaced it.

Ashley
Click to expand...

My Seeley 850 is the only Norton I have ever owned. The single cam is a bugger - but in every other way, the motor is much better than any Triumph I have ever owned. Which at last count was about ten. Getting the Commando motor going fast and reliable was dead easy. You just don't rev it too quick. I use a Manx clutch and single row primary with a floating engine sprocket. It never slips, although the engine pulls like a train.
 
All my Triumphs have been very reliable except for the 79 Bonnie I brought off my Brother in law it sat out in the weather with just a tarp over it for years without been rode, I got it cheap off him and had it running the next day but had to put the Norton mufflers on it as the Trumpy ones were rusted out, had it for 12 months and got sick of it every time I rode it things would fall off it or things would break, it nearly broke my sprit, my 81 Thunderbird was my best bike it never let me down at all in the 9 years and clocked up 250k kms on that bike and only done a top end rebuild before I sold it, I also ran a Joe Hunt maggie on that bike.
My modren Thruxtons are also very reliable but they have some time to prove themself's yet but I love the torque of the 1200 hp motor, it feels as good as my Featherbed and handles as good with a lot more torque.

Ashley
 
Hi All
Thank you to all for your advice.
I have decided to go the route of using fibre plates.
Should I soak them in Castrol TQF before fitting ?
Thanks
 
IMO do not soak them first. I've experienced on two bikes where the plates tend to stick together
when held tight together due to being wet with oil.
 
rvich said:
I love clutch threads. First, people often confuse the "pressure plate" with the diaphragm. I think we have to accept that even speaking the same language, that we don't. The oil you put in the primary should not be soaking the plates down in the first few miles. If it does then I would think the primary is over-filled. If that is the case then the type of oil may have a significant impact on clutch grip but otherwise no. Unless the stack height is so low that the diaphragm can't place adequate pressure on the stack then I would suspect there is something wrong with the adjustment or assembly. Is the center notched from running bronze plates? Is it possible the plates can't make contact because they are trapped in the notches?
Click to expand...

This would be my first assumption as well, check the center for notching, confirm the stack height is adequate and double check the lift adjustment at the hub

acotrel said:
My Seeley 850 is the only Norton I have ever owned. The single cam is a bugger - but in every other way, the motor is much better than any Triumph I have ever owned. Which at last count was about ten. Getting the Commando motor going fast and reliable was dead easy. You just don't rev it too quick. I use a Manx clutch and single row primary with a floating engine sprocket. It never slips, although the engine pulls like a train.
Click to expand...

whoa there... I love me my norton, but I wouldn't trust it to carry me down to Baja, up the pacific coast, then back east across Canada like my TR7 did ;)
 
Wrong friction plates (thinner) for your bike???

http://atlanticgreen.com/clutchpak.htm


Friction Plate

Early-thick .145” friction plates Qty =4

Thru 70- bonded segment 06-0749

71-72- solid fiber 06-1339

Barnett- bonded segment-thick # 524-68


Late-thin .125” friction plates Qty=5

73-75 Bronze 06-3741

Barnett-bonded segment-thin # 524-73.
 
Dave’s SOLID, not anecdotal information allowed me to build the PERFECT clutch, the first time. Smooth as buttuh, no drag, progressive.
 
  • Like
Reactions: baz
Hi All
Thank you for the further replies.

I am aware of the fantastic Atlantic Green web site and try not to ask questions answered there.

My clutch centre looks to be almost new. I must have fitted a new one in the not too distant past.
(This getting old business is not good for me!) And the basket teeth are not notched.

Although I stated in my first post that I had not seen any gearbox oil contaminating the red TQF in
the primary chain case the hole through the mainshaft is full of gearbox oil.

However, the end of the main shaft is outboard of the clutch plates and surely centrifugal force would
tend to fling it to the area of the circlip of the clutch basket during riding and then drip down into
the bottom of the primary chain case when stationary and not onto the plates? Happy to be corrected.

Please correct me if I am wrong, but Norton fitted a bronze clutch originally designed for dry use in
a wet use on the Norton?

Is the surflex clutch more tolerant of wet use?

What is the consensus of opinion on the best suppliers of a clutch nut with a seal?

Off to see Fleetwood Mac now, and Italy (Pugia) next week, so sadly no more application of spanners!

Thanks
 
I've been dialling in my bike over the last while after getting some engine work done. I had already done the clutch stack height & have the oil seal nut fitted on the clutch so no gearbox oil can get into the chaincase. I have the original bronze plate clutch plates.

While doing some plug chops I noticed I was getting clutch slip with hard acceleration from 70-90mph.

I went back through the basics of setting up the clutch & realised I had not set it up correctly. I had not checked that the actuating arm was loose in the gearbox before I adjusted the clutch adjuster!! I did the adjustment by the book & it made a big difference.

Just back from a 30mile spin, lots of 80-100 mph hard acceleration stints & no clutch slip.

High speed runs all done of private roads :rolleyes:
 
ashman said:
Set up right, run the right oil if running chain, not over filled with oil, or run dry with belt, adjusted right and they don't slip at all.
Click to expand...
I've never seen another bronze clutch, although I know they use similar material in earth mover brakes.

Run dry with a belt, I could agree, but any small quantity of oil gets in the basket and they slip.
There must be a good reason why nobody else ever put bronze plates in their clutches. Since most are wet, it stands to reason, but even rattly dry Ducati clutches use fiber plates. The bronze clutch in the SS clone slipped whenever it came on the pipe at 4500 rpm.
 
Staytite said:
However, the end of the main shaft is outboard of the clutch plates and surely centrifugal force would tend to fling it to the area of the circlip of the clutch basket during riding and then drip down into the bottom of the primary chain case when stationary and not onto the plates? Happy to be corrected.
Click to expand...

You have mixed up the gearbox component locations!
the circlip is:
1. at the OD of the main shaft
2. near the end of the sleeve gear
3. far short of the mainshaft end, yes at the back and outside of the clutch drum.

The C Clutch Rod Seal is:
1. at the end of the main shaft
2. seals the main shaft center bore where the push rod lives and where the gearbox oil exits INTO the clutch/plates (inside the clutch drum).
3. The ccrs does not fix the other clutch contamination from the primary oil.
 
Last edited:
Danno said:
I've never seen another bronze clutch, although I know they use similar material in earth mover brakes.

Run dry with a belt, I could agree, but any small quantity of oil gets in the basket and they slip.
There must be a good reason why nobody else ever put bronze plates in their clutches. Since most are wet, it stands to reason, but even rattly dry Ducati clutches use fiber plates. The bronze clutch in the SS clone slipped whenever it came on the pipe at 4500 rpm.
Click to expand...

As I said above my bronze clutch is not slipping now, once I adjusted it 'by the book'. I have Castrol Classic XL 20W50 oil in the primary (It's a MK3 with sprag etc. so no ATF)

I had the bike 'on the pipe' between 4K-5.5K revs. Time will tell if it will stay like this!!
 
Last edited:
Status
Not open for further replies.
Back
Top