HB: Handlebars Handlebar Levers

[bmetcalf]

These plain end levers are available at a very good price. They tell me that they measure 1-1/8" between centers of the pivot and the cable end, which I think is the needed length.

http://www.bmikarts.com/Universal-Lever-Brake-Clutch_p_5149.html

 

[Simon Dinsdale]

I have noticed that the current reproduction levers available the actual lever length from the tip of the lever to where the cable nipple mounts is now shorter. So the lever doesn't go across the whole handlebar grip. Try putting an old lever against new and you will see the difference. Its bound to effect the mechanical leverage from your hand.

 

[davidd]

I think many owners use 1-1/8" levers, although Neville Higgins mentions the .906" pivot distance as being correct and original design. Most call this 7/8".

Emgo makes the repro Amal aluminum levers that are 7/8" pivot distance. They are Emgo 32-69651 or 2 for brake or clutch respectively. Emgo may also make a 7/8" pivot distance in the Doherty style, but I could not find a part number for them in a 7/8" pivot distance.

I am not sure if the plain chrome levers are available, but I see reference to them at AMC Spares.

I think that Coventry has levers with pivot distances of 7/8", 1", 1-1/16" and 1-1/8." I am not sure about the styles.

The sweet spot for the lever is measured to the middle finger, or there abouts, assuming that it is not being used as a traffic signaling device. Shortening the lever width would certainly choke up on the lever ratio.

http://www.amcclassicspares.com/Cables & Control Levers.pdf

David

 

[bmetcalf]

I thought the 1-1/8” was right. My levers are that size and I got them from Big Sid in 1984. Oh, well, they are fine and I’ll live with them and pass on the new ones.

 

[TouringGodet]

My original Bowden lever is 1-1/8". My replica Michael Breeding solid levers are 1".

 

[davidd]

Know Thy Beast, page 78 last paragraph:

"To get the same leverage, replacement levers should be 7/8 in. between the centres of the pivot bolt and the nipple."

When you do the math, according to the Prof., the hand pull force is multiplied times the lever ratio and that number is then divided by the pivot distance. Thus, the smaller you keep the denominator (the pivot distance), the larger the force will be to the cable. By his calculations, going to a 1-1/8" lever from a stock 7/8" lever will decrease the force to the cable (and then eventually the shoes) by 86 lbs. That is significant.

David

 

[Simon Dinsdale]

Know Thy Beast, page 78 last paragraph:

"To get the same leverage, replacement levers should be 7/8 in. between the centres of the pivot bolt and the nipple."

When you do the math, according to the Prof., the hand pull force is multiplied times the lever ratio and that number is then divided by the pivot distance. Thus, the smaller you keep the denominator (the pivot distance), the larger the force will be to the cable. By his calculations, going to a 1-1/8" lever from a stock 7/8" lever will decrease the force to the cable (and then eventually the shoes) by 86 lbs. That is significant.

David

So is it best to have 7/8 pivot distance for the brake lever for max braking force and 1-1/8" pivot distance for the clutch lever for max clutch lift?

 

[nkt267]

So is it best to have 7/8 pivot distance for the brake lever for max braking force and 1-1/8" pivot distance for the clutch lever for max clutch lift?

I would certainly recommend that for a Comet,it's what i have. I followed advice given years ago before the advantages of the forum.

 

[vibrac]

I am using alloy levers with 1" pivot distances on the 2020 Comet so I am halfway (and I am researching a motocross easy pull clutch system as the Honda clutch with 7/8" is still a pain). I selected the alloys not just for the weight but mainly because it has an integrated brake switch and a twin brake cable pull pivot which means... (No NO I am sorry lets not start that beam argument again!

 

[greg brillus]

Just as a point of interest, talking about bad clutches and trying to gain more lift to help the problem. On the batch of new series"A" twins we have here, and the three I have ridden..........This is with completely refurbished prewar Burman gearbox's, but using a belt drive primary and some kind of new Norton style diaphragm clutch running basically dry. The nicest looking compact clutch you could imagine.............These bikes select first gear with absolutely no crunching into first, shift perfectly through all the gears and select neutral everytime even when hot ..........Not too different to a modern. This is quite a contrast to the usual post war Comets crunching into first and not much better thereafter. This proves to me that the clutch and/or issues relating to it are the major fault in the equation. This was a big surprise to me when I had ridden these bikes, by comparison to the norm ................Something to ponder...................Cheers................Greg.