1969 750cc Dunstall Norton
- The 144mph Drainpipe
Paul Dunstall was Britain's leading tunder
of Norton twins in the Sixties and early Seventies.
The enterprising South-East Londoner bought
left-over parts from Norton's Domiracer project
when the Birmingham factory closed in 1963,
and used them as the basis for onward development.
Bright red Dunstall Domiracers were highly effective
on the track and the 130mph Dunstall Atlas roadster
was the fastest motorcycle on the market.
In 1967 750cc Dunstall rider Rex Butcher collected
a bunch of world records at Monza in Italy,
including one hour at 126.7mph. In 1968, Dunstall
rider RayPickrell won many short curcuit races
on a Domiracer, as well as winning the Isle
of Mann 750cc Production TT on a Dunstall Atlas.
The ultimate Dunstall Norton racer was built
for 1969, featuring a new frame to cope with
the 70-plus horsepower that the team was wringing
from Norton's 750cc Atlas engine. Designed by
Eddie Robinson, who also worked for the Seeley
equipe, the open-bottomed oil-carrying structure
has a spine of large-diameter tubes that earned
it the drainpipe nickname.
Experimental pannier fuel tanks inside the
fairiing on this machine are intended to lower
its centre of gravity and improve handling.
However, no fuel pump was fitted and starvation
problems saw the Dunstall team revert to a normal
tank for most events.
During 1969, Pickrell rode Dunstall machines
to gain two speed records. One, thought to have
been set on this machine, was a new national
record for the 750cc flying-start quarter mile
at 144.69mph established at Elvington, Yorkshire.
The other, set on another Dunstall team visit
to Monza, was a world 750cc record for 10 Kilometres
covered at 131.51mph, which stood for seven
Engine - 745cc (73 x 89mm) are-cooled overhead
valve parallel twin, 10.25:1 compression ratio,
two 32mm Amal carburettors, Lucas magneto
Transmission - Chain primary drive, dry
multiplate clutch, five-speed gearbox, chain
Chassis - Tubular spine frame, telescopic
fork front suspension, swinging arm rear suspension,
Wheels - 18in
Power - 72bhp @ 7000rpm
Top Speed - 145mph