why is the norton atlas clutch such a bear?"

Re; “I asked a question in reply number 18 .... is there any backlash when engine braking? That question was meant to explore whether the cratering problem is worse with the Heinz mod. I can visualize the plates slamming back and forth in that 19 degree gap in the clutch basket when suddenly engine braking. Not saying that such slamming will happen, but just a concern. So far no answer from John on that point.”

Of course there will be, the same will happen when you roll the throttle back on, that is probably the only downside, it would be far better engineering solution if ALL the clutch basket slots were cut 19 degrees.
 
@Bernhard #81

Agree! That is what I was referring to when I said "back and forth".

But where are we to get a basket with no slots to start with?

Now you are talking about solving the problem starting with a blank sheet. If we have that prerogative, let's go with the technology that Knut made us aware of in #73.

Slick
 
Re; "But where are we to get a basket with no slots to start with?"

Assuming you can find some, you then have the problem of machining, which could be overcome-I would use a long nose end mill, and as the slots are at 19 degrees there will be a 19 degree wedge at the bottom, I would simply file those out flat. . . . .
 
texasSlick said:
But where are we to get a basket with no slots to start with?
Click to expand...

Andover Norton has the baskets made by someone. You could approach AN and beg to buy a sample which hasn't been heat treated. Having this, you could weld up all the slots professionally, have them machined the way you want them, and finally send the basket off for heat treatment. Or, you could also ask if AN's supplier will make you a special. After custom machining the basket it should join the normal process run.

-Knut
 
Bernhard said:
Re; "But where are we to get a basket with no slots to start with?"

Assuming you can find some, you then have the problem of machining, which could be overcome-I would use a long nose end mill, and as the slots are at 19 degrees there will be a 19 degree wedge at the bottom, I would simply file those out flat. . . . .
Click to expand...
Originally Heinz (when he worked for Norton at Brace Bridge Street) had un-machined clutch centers that he machined, those are long gone and that is why they went and machined the clutch baskets. If you are going to approach AN why not ask for un-machined clutch centers?
John in Texas
 
Bodger said:
IIRC there is a difference between the profile of the Dommi clutch operating lever (in the gearbox) and the Commando clutch operating lever. Years ago I swapped the clutch operating lever on my 650SS for a Commando operating lever and it significantly reduced the effort needed to disengage the clutch. On the other hand the clutch does not fully engage until the handlebar lever is nearly fully released, but that is a phenomena that I have noticed on a number of Dommis over the years.
Click to expand...

i studied the actuating lever profile and reprofiled it by tig welding stellite on it and grinding ,it had poor lift and would barely lift the 4 spring triumph belt drive unit causing clutch drag
i wonder if fitting the earlier scroll type arrangement would be a better bet

i made a set up on a 5 speed racing box
that the pushrod came through the outer cover with a hinged lever and a boss to take the outer cable this worked perfectly
if looking a bit vintage oil sealing on the push rod was a small o ring on the pushrod sliding in an alloy tube
 
Bernhard said:
Re; "But where are we to get a basket with no slots to start with?"

Assuming you can find some, you then have the problem of machining, which could be overcome-I would use a long nose end mill, and as the slots are at 19 degrees there will be a 19 degree wedge at the bottom, I would simply file those out flat. . . . .
Click to expand...
I have changed my mind, and would hold the clutch centre in a mantle and use a modified standard cutter in a horizonal milling its quite easy when you know how, you just need the right machine with a dividing head.
 
the modified basket is a very good idea but for the average person who wants to make the clutch work with moderate hand pressure and low cash outlay, what I have done on 2 Atlases and one dommie is to use the Emgo remakes of the old Spanish Amal levers found on Bultacos etc. The look great and are less than $30 for the pair. A slight modification I make is to drill the lever so the cable barrel fitting will fit all the way through. Normally there is an open side and a closed side on the lever. The closed side is for appearance but requires filing the cable barrel fitting on one side. It looks better, though. Next is to fit the Commando operating lever in the right side of the gear box and, of course, pay close attention to cable routing. I use Tri-Flow to lubricate cables, need to renew every two months.
 
seattle##gs said:
..... Next is to fit the Commando operating lever in the right side of the gear box .....
Click to expand...

Not say'n this does not work, but everything I have read (most of it on this Forum) says do not mix the respective clutches and their respective operating levers. ???

seattle##gs said:
..... pay close attention to cable routing. I use Tri-Flow to lubricate cables, need to renew every two months.
Click to expand...

Agree, cable routing is important, but a greater improvement in hand effort would be to use a Venhill Teflon lined cable. They reduce effort by about 25%.

Barnett clutch plates are designed to run in oil, and have a greater coefficient of friction, thus the clamp force can be reduced by a turn or two on the spring adjuster nuts. Couple Barnett plates with reduced clamp force, ATF lubricant in place of oil, and the Atlas clutch becomes a Panda bear cub. Still four finger however.

Slick
 
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