U.S. Specification

Well I never, I didn't know that the lucky chaps in the U.S. were able to buy Mk111 style double-disc machines as early as 1969 :shock:

What else have you been keeping to yourselves ?

http://cgi.ebay.co.uk/1969-NORTON-BLACK ... dZViewItem

It could well be a 750 frame. I wonder how he finds the 850 fork angles ?

Hopefully the (lucky?) new owner will know what he/she has bought/won (a bitsa)!!

(although, judging by the current bid amount, -probably not!)

There weren't even any single disk-brake machines coming out of the factory in 1969. When I left in mid-1968, they were still dinking around trying to get a sliding disk with a fixed caliper to work.

Imagine a steel disk about 11" diameter being pushed really hard at one small place on the outermost 2" of its surface, then trying to get a reasonably good sliding motion at about 2" radius from the center on a splined aluminum hub. It jammed every time and buckled the disk.

The next try was a ring of drill-rod dowel pins in the hub and matching holes in the disk, but still on a 4" pitch circle diameter. Just getting all those dowels parallel was a toolmaker's job, not a produtction tolerance set-up.

They hadn't figured out a single-piston, sliding caliper with a fixed disk, which is now common everywhere, so they soldiered on with that wimpy Italian (Campagnolo?) twin-leading-shoe drum brake at least through the 70 model year (I think).

If there was a dual-disk set-up in the US, it must've been after-market, or maybe another wild idea from Berliner.

frankdamp said:

If there was a dual-disk set-up in the US, it must've been after-market, or maybe another wild idea from Berliner.

Click to expand...

The eBay bike just has a load of later parts fitted, like the the 1975 850 Mk III wheels, swinging arm, brakes, fork yokes, Z plates..etc. etc. and it has a few other odd bits, the seat looks like the '73 type, and the tank is a later steel Interstate one. I suppose if mixing and matching parts keeps another Commando on the road then that is not such a bad thing even though it has obviously been misdescribed by its owner in the listing?
Although I think I'd want to change those 850 yokes for 750 ones as I expect the high-speed handling could be 'interesting'?