P11 brake, clutch and choke levers

I have seen 2 versions of hand levers used on P11s. It seems the factory had several different suppliers for these parts. My bike actually has aluminum levers, but the lever action is pretty stiff due to the different fulcrum point, we believe. I have seen steel levers with various size balls ends. Does anyone know what would have been correct on a P11a?

The ones on the left look huge.

If they all have the 7/8 inch distance between the centre of the pivot pin and the centre of the clutch cable nipple, they, they probably all correct depending on year.

As far as I am aware the Burman / Norton / AMC clutch was designed to employ a lever with a centre distance between centre of pivot and cable nipple of 7/8 inch. If my memory of Mechanical Engineering classes at Technical College are correct by using levers with a centre distance of 1 1/16 inch all you do is increase the lift which = more work being done and make clutch lever action heavier. i.e. NOT a clever thing to do especially on an Atlas because initial release load is around 250lbf and at full lift around 300lbf...so Mr Hele informed me many years ago as we discussed the qualities clutches were SUPPRESSED to possess which are that they should
1. NOT slip when fully engaged, even when hot. (Some friction materials expand when hot).
2. free off instantly and without drag whenever required even when hot.
3. be EASILY operated by the user at all times.(Tell that to Atlas and T140 owners!!)
4 possess the LIGHTEST rotating weight reasonably possible. I.E they should NOT be an unbalanced gearbox breaking flywheel as are Commando lumps especially when fitted with bronze plates.

Yee goda it was bad enough that the 'brains' at AMC reduced gearbox speed compared to the Atlas thus increasing the torque through the already overworked gearbox that had been designed for motors putting a lot less grunt through them but to go and stick a ridiculously heavy unbalanced flywheel on the end of the shaft so far away from the main bearing...I believe Peter Williams to get the gearbox to actually stay together for a lap of The Island stuck a correctly mounted and located bearing behind the clutch, reduced the mass of the clutch and speeded up the box reducing the torque through it. Mind you I suppose having the box fail at about Bishops Court and coasting down to the pub at Ballaugh was OK especially if it was raining!!!

My Ranger has a 7/8" Doherty lever with the adjustment wheel, similar to the third from the left in your pic. Adjustment wheel up at the lever is nice.



This pic is from Andover Norton, but I don't know if they're 7/8" or 1-1/16", and are listed as early Commando

J. M. Leadbeater said:

As far as I am aware the Burman / Norton / AMC clutch was designed to employ a lever with a centre distance between centre of pivot and cable nipple of 7/8 inch. If my memory of Mechanical Engineering classes at Technical College are correct by using levers with a centre distance of 1 1/16 inch all you do is increase the lift which = more work being done and make clutch lever action heavier. i.e. NOT a clever thing to do especially on an Atlas because initial release load is around 250lbf and at full lift around 300lbf...so Mr Hele informed me many years ago as we discussed the qualities clutches were SUPPRESSED to possess which are that they should

Click to expand...

+1

Anyone try the repro-levers from Andover Norton?

Bill,
When did the factory switch from non-adustable to adjustable? On Rangers only?

Anybody know if levers should be 7/8 pull or 1-1/8 pull?

Also, clutch side, is the perch supposed to be a horizontal clamp or vertical clamp assembly?

From what I understand, horizontal clamp was used for manual advance applications.
P11 of course has an auto advance.

I have seen P11 clutch levers with both types vertical and horizontal perch clamps.

Which is correct??

elefantrider said:

Bill,
When did the factory switch from non-adustable to adjustable? On Rangers only?

Click to expand...

I would think Ranger only. I don't know, but my guess is the Ranger used the same levers as the 68 Commando since they were built after the 68 Commando production run.

Rangers also have a brake switch in the front cable, unlike earlier P11s

Hi Elefantrider ,

I am not a P11 owner but my understanding when researching the topic for my 650ss is that the clutch (same as P11) must be 7/8" to get the lightest pull (this is specified in the workshop manual). I also found out that Norton specified 1 and 1/16" for the brake lever. However 7/8" for the brake would result in a lighter pull but Norton thought this might make the brake too sharp!!!! I'd go for 7/8" each side.

Hope this helps,

Graham

elefantrider said:

Anybody know if levers should be 7/8 pull or 1-1/8 pull?
Also, clutch side, is the perch supposed to be a horizontal clamp or vertical clamp assembly?

Click to expand...

Clutch and brake operation were designed for 7/8" pull (fulcrum to cable distance) by AMC. This is standard fitment on all "pure" AMC bikes.
Lever clamps were always of the vertical assembly type.
There are probably pictures in one of Bacon's books. I have a factory press photo of a '63 G12CSR showing rider's view as further evidence.

Regards,

Knut Sonsteby

Thanks for all the feedback. I am looking for old test photos or brochures.

Found this one.
Anyone with good eyes and possibility to zoom in, does the clutch side clamp look to be vertical or horizontal?
Looks vertical to me.

download/file.php?id=794

The right brake side with choke sitting on top needs a horizontal clip (hard to make any other way).

The left side clutch should also have a horizontal mount/clip according to Waldridge Motors:

"Correct would be made by Amal with horizontal clips both sides. "

Anyone have more press photos showing the bars? This is where a dedicated P11 history book would be helpful but if we havent seen one so far, doubt one will ever be done. Good thing we have this site as a resource. Eventually, it will contain more helpful p11 info and images than in a dedicated book.

elefantrider said:

The right brake side with choke sitting on top needs a horizontal clip (hard to make any other way).

The left side clutch should also have a horizontal mount/clip according to Waldridge Motors:

"Correct would be made by Amal with horizontal clips both sides. "

Click to expand...

I stand corrected. After thorough investigation incl. examination of photos, the combined choke/brake lever is definately horizontal. Although images are a bit blurred, it may be concluded that the clucth lever is horizontal too. Same lever was used on the G/N15 and here the lever clamp is definately horizontal.
Contemporary fitment on Triumph bikes, the levers and fixings look to be identical (see figure 27).
http://www.hermit.cc/tmc/parts/dex_f.htm

-Knut