Scott Newsletter 8 - Scott Technicalities

more importantly, the sustained accuracy of the spark timing. The results showed that where I
had imagined that the power was limited by the engine breathing efficiency, it was, in fact, being
limited by the magneto spark losing its timing in a similar way to a four stroke engine having
“Valve bounce”. I designed and made a conversion to a BTH magneto using PVL components
which brought further improvements. When Tony Harris started to make his new BTH
magnetos, I was happy to try this with great success.
In 2003 I crashed heavily at a race meeting in Anglesey and because of injuries was unable to
race. Tony Harris suggested that I contact New Zealander Paul Dobbs to see if he wanted to
race the bike. Paul had never raced such an old rigid bike before and initially, he was very
unhappy with the handling. He suggested that there was not enough weight on the front wheel
and so the seat and bars were re arranged. Paul pronounced himself satisfied and remarked
that he had never experienced such a high degree of feedback from a bike and that this gave
him great confidence to use it hard gaining spectacular results.
As an engineer who has spent his life designing and building special machinery, this bike has
been a very stimulating project. The Scott would not be the first choice if success were the
absolute goal. There is a bigger hill to climb than, for instance if you pick a camshaft Norton. If
the reader is concerned at the amount of special engineering that has gone into this bike, then I
assure you that almost all of the other successful historic race bikes are highly special inside
and use alcohol fuel. The Scott uses unleaded pump fuel! The development has taught us
which modifications bring the optimum results, first as regards durability and reliability and also
as regards gaining power and smoothness without sacrificing the high torque characteristics of
the Scott engine.
Design mods and component changes to the Moss Special.
Component Changed to Reason
Frame (1)
Frame (2)
Forks
Forks
Forks
Brakes front (1)
Brakes front (2)
Lower frame rails removed
Lightweight frame made
Modify friction dampers
Cast silicone rubber in spring
Phosphate treat
Fit two Webb drums
Make new better copies
To give cornering clearance
To reduce weight and increase stiffness
To enhance damping
To enhance damping
To protect corrosion but still see any cracks
To improve braking
To improve braking
Edition 7 ­ 28 – 2006