TOPIC: Commando Isolastic evolution

The iso's have two functional components. INNER column and OUTER column
The inner column is hard bolted solid to the frame tabs.
The outer column is held off the rigid frame via rubber ISO mounts.
The internal rubber components provide compliant connection and support between the inner and outer columns.

The inner mount is comprised of stacked component on the center bolt. All together they comprise the "stacked length" between the two 06-0422 front engine mounting collars These collars also restrict movement of the 06-3556 PTFE or urethane washers during drive train nutating motion.

The outer column floats on the rubber iso's installed in the 06-1410 front engine mounting. This body and two tube caps are shorter then the inner column. The "freeplay" between the inner and outer columns is adjustable using selected captive shims to reduce the gap to the desired amount. Typically 0.010" or less.

REAR ISO RATES
Dan Battle wanted to salvage a swing arm from his "donor" engine cradle. Well try as I might, oil soak, 20 ton press, oxyacetylene torch, I finally had to admit defeat. A thin abrasive wheel on my buck-eye grinder strategically cut the swing arm free from the cradle. I saw something new to me...an unfamiliar ISO rubber. As I typically have curiosity when I see something new on a Norton part, I had to dig in.
I will be starting on this series 1 Commando REAR ISO MOUNT which contains, to my surprise, a METALASTIK 13/1782 unit pressed into each end. The construction is a cured&molded rubber in between an outer 1-1/2" steel tube and inner 1/2" steel tube. There is also a steel tubing spacer to create the required full length dimension. According to the parts book, there should also contain secondary rubber buffers sitting on the inner tube.
pix
I have done some new tooling to measure the longer REAR ISO rubber stick assemblies. To enable use in the fixture, I had to torch cut the ISO housing tube out of the engine cradle and lathe cut off the residue furnace braze and steel plate. A pix of the new ISO measurement rig, I first set up around 20+ years ago, to do my first graph of the front ISO deflection rates of various rubber size and hardness.

pix

Mounting and compressing the later ISO components within the tube significantly contribute to the isolastics compliance rate.
You may note others trying to determine ISO compliance rate based on surface durometer.. laughing..
sorry that doesn't work... thumbsdown

pix


Now to dismantle this early Commando rear ISO 06-0432 ? metalstic insert and it's additional spacer/buffer items. Note in the graph the kink in the line starting about .070", I'd bet a beer that is the clearance until the secondary internal buffers become restrained by the ISO housing tube. Though I can't see them (yet), I think this proves they are there. beerchug

FRONT ISO RATES
One set of "discrete components"(upper left) and 2 each "rubber on a stick". One from many years ago(center) and one new soft style(right) untested and not measured yet...on far right are packs of end play shims, .005", .010", .020', .030" for setting "discrete component" end play.