Dunstall twin disc front end

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Aug 28, 2019
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Where can I find more info on the Dunstall twin disc front end?
A friend of mine bought a Commando in pieces from an estate sale, and in the sale was a Dunstall twin disc front end in pieces which he wants to use on the bike.
He wants to know if Dunstall used his own yokes, his own stanchions, dampers a.s.o.
Any and all info is greatly appreciated, thanks.
 
I can't answer your technical question, but in response to the "more info" first question, I seem to recall reading numerous mentions of the overall effectiveness of the Dunstall dual disks to be less than what most people expect from dual discs. Certainly they overheat quicker, due to smaller disc size.
 
Hi Robban
A few things.
There are I believe three different size discs.
The caliper pistons seize & gall the caliper when you try to remove them.
I don't have the measurements to hand but the piston seals are a plain o ring.
The internals in the set I had were standard Dommie although I had damaged spares in Manx length.
Dunstall sold his own yokes, although mine were not marked with his name.
You need to find the Dunstall catalogues/brochures but I'm not sure how much info they will give you.
Good luck
 
I don't know if this will help much, but here are two snips for Dunstall catalogs showing the early style, which used separate, bolt-on, Airheart style calipers, with a mounting plate that clamped onto the stock slider, and the later style with integral calipers.

Early Disk Brakes from 1969 Catalog.jpg


Disk Brakes from 1973 Catalog.jpg


Ken
 
I always thought they looked super cool with the caliper incorporated in the slider
 
I've heard stories that heavy braking transfers heat to the fork oil, and affects the handling, but I had two friends who raced successfully with them in vintage classes with no issues, so I'm not sure how much truth there is in the story. I suspect they would be fine on a street bike.

Ken
 
I was told by a racer who ran them in the day, that they overheated the fork oil. He also said that Phil Read said the same. However, nobody went back to drum brakes! Along with most of the grid they only got changed out when the AP Lockheed calipers & suitable forks became available. The earlier set up before the cast in caliper fork legs.
 

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