Four dream days with Peter Williams.

Here is the history from the Dunstall 500 Lowboy Norton


Dear Yves

In the 1958/59 seasons, Paul Dunstall raced a home-built 600cc Dominator Model 99 for Club Racing. His close friend, Fred Neville, raced a 500cc Gold Star BSA. At a practice day the two riders swapped bikes to compare performance. Neville lapped much faster on the Dominator than Paul had and, shortly after the test runs, Paul suggested that Fred should race the Norton 99 Special in unlimited class races, resulting in good finishes which put the name Dunstall on the map.

In 1960 Norton Motorcycles built a batch of lowboy frames for 500cc racing twin engines to race in 1961. A fantastic third place finish in the 1961 IoM Senior TT Race with Tom Phillis justified the project. It was the first push rod engine motorcycle to lap the TT circuit at over 100mph.

Norton MC built a number of Domiracers with both lowboy and Manx chassis as 500cc and 650cc machines.

At the closure of the Norton works in Birmingham in 1962, Paul Dunstall was invited to bid for the race development twin cylinder bikes and parts. On arrival at Bracebridge Street he loaded his van to the max with very special parts and headed back to London.

In 1962 Dave Downer rode for Paul in 350cc, 500cc and unlimited classes, all using the low boy frames. Sadly, one year later Downer lost his life following a crash at Brands Hatch with Derek Minter, who was seriously injured.

With riders like Dave Degans, Griff Jenkins, Rex Butcher and Ray Pickrell, Team Dunstall had good results with both 650cc and 750cc bikes in low boy frames for six seasons until Paul developed a special Dunstall large diameter tube frame machine as he had reached the limit of the low boys handling with the more powerful engines.

I purchased my Norton framed machine in 1988 as a box of parts. The engine was rebuilt by the late Graham Sanders who had worked with Doug Hele at the Norton factory in the 1950’s. The engine is a standard 66mm x 72.6mm bore and stroke, non-squish Head with big valves, needle roller bearing camshaft with pressure end oil feed, twin 30mm Amal GP cards, Lucas rotating magnet flanged magneto made by Lucas for special race bike projects. The gear box is a 5-speed Schafleitner unit with a Manx clutch. The front brake is an Oldani unit, the rear brake is a Manx conical. It is lighter than a standard Manx Norton with better acceleration but with a similar top speed, Paul Dunstall offered a Dunstall designed frame kit in the late 60’s. It had similar dimensions to the Norton frame but had a modified top tube arrangement.

It is suggested that, had Norton continued in Birmingham, the Domiracer would have replaced the Manx Norton single cylinder machine with a new, stronger Domi engine designed as a race engine, not a converted, much modified road based engine. Who knows what might have been!

Regards


Michael Braid








On 19 Feb 2017, at 12:32, marina.kips@skynet.be wrote:


Hi Michael,
Thanks for coming to Wieze, it was realy great
I post the story on access norton forum, but someone wish to know more about the history from your Dunstall Domiracer, can you give me more details Please?
Best Regards
Yves

You can see the pictures of the Dunstall 500 Domiracer on "other Norton"
Yves

Don't have any pictures of a "truxton200miler", but this is the bike from the Thruxton 500 mile race in 1973. Taken form one of the Commando ad brochures.



For comparison, this is the Croxford factory PR from the same ad brochure.



Ken

thanks , that answers the question who was at the helm as well
and that it was a 500miler instead of 200 (stupid me ; must be old age again)
funny that the gearchange in this pic is simply a reversed gearlever and not the welded outer cover mod like the 72 jpn

ps forgot to mention that the rear brake is a manx drum ( not many production racers have that ) but when working on the bike you see it bristles with many , small mods , and very unlike a 'std' production racer
this was a norton home brewed special for that one race

info came from 79x100 , who had the bike build as an exact replica by the original builder , Norman White
79x100 was later knocked from his own , VERY NICE , std commando 3 weeks before his wedding and so lost his appetite for clip-ons etc , so the bike passed through my hands to Kobo
i am lucky to be allowed to spanner on it, and modified it a bit for easier use because this baby IS going to be used on the road

I wonder if Norton did the mod PW suggested for the Brands Hatch short circuit, that its move the whole engine and gearbox 3/8 inch over to the left so it could lap the circuit quicker :?: :shock:

Bernhard said:

I wonder if Norton did the mod PW suggested for the Brands Hatch short circuit, that its move the whole engine and gearbox 3/8 inch over to the left so it could lap the circuit quicker :?: :shock:

Click to expand...

I would think that would cause problems with ground clearance on the left. Racing a stock PR back in the '70s I had enough problem with dragging the primary case that I had to have it machined at an angle and a plate welded on. Moving the engine over to the left would just make that worse. Maybe Brands doesn't have many left turns?

Ken

lynxnsu said:

yet another mistake at making this a production racer, it is NOT
engine was shifted to the right , exhausts were on the righthand side , both for ground clearance , amogst other mods
bike was the brainchild of peter williams but i forgot who drove it at truxton
also primary chaincase was modified for clearance
there was an article about it in classic bike umpteen years ago
seems like everybody thinks it is a caferacer(hate the word and most of the bikes called that) or a production-racer

ps it is not my bike but i did some work on it after it left England
ps2 if some-one could put a pic of the bike that would be great

Click to expand...

engine was moved to the RIGHT and both exhaust exited on the RIGHT to give ground clearance on the left , they ran anti clockwise so loss of ground clearance on the right made no difference . this bike was build for that circuit and that race alone
the primary on the bike at the show is narowwed by 2.5 cm
as the engine is now in bits , i cannot put a pic here
my own bike has got a narrowed primary as well, will post a pic later on
this narrowing made chapfering the primary case unnecesary ( sorry if my english is not very correct , too much chimay yestezrday)

Thruxton 500 miler has been run at CASTLE COMBE CIRCUIT, Thruxton, Brands Hatch, SILVERSTONE, DONNINGTON PARK, until 1983 for results look here;

http://www.sdmcc.net/files/SDMCC%20Raci ... 201983.pdf


Engine for the 2 production racers for Brands Hatch short circuit only -it was used on no other circuit-was moved to the LEFT :!:

Bernhard said:

Thruxton 500 miler has been run at CASTLE COMBE CIRCUIT, Thruxton, Brands Hatch, SILVERSTONE, DONNINGTON PARK, until 1983 for results look here;

http://www.sdmcc.net/files/SDMCC%20Raci ... 201983.pdf


Engine for the 2 production racers for Brands Hatch short circuit only -it was used on no other circuit-was moved to the LEFT :!:

Click to expand...

i suppose you have to come and look for yourself, always welcome
her is a pic of the primary , but not on the race replica but my own bike


ps am i missing something , i can only find results for thruxton , and only till 73 ?(using your li nk)
but i am no historian , and do not claim to know all , my point was that the bike is not a production racer , and surely not a caferacer , but an exact (according to norman white ) copy of the bike used for that race
THE END

brilliant read and photo's thanks for posting

I hope I can clear this confusion up regarding the position of the engine/exhaust e.t.c.
The British mainland race circuits were used in various formats, clockwise and even anticlockwise for the Hutchinson 100 at Brands Hatch;

http://www.bing.com/videos/search?q=hut ... &FORM=VIRE


I assume Norton would do whatever it was necessary to make the best of the production racer that they used to obtain the best ground clearance, which is always a problem on the production racers HTH