Over
previous decades there have been many restrictions imposed upon
motorcyclists in various forms. Some these being :- the compulsory
wearing of safety helmets, exhaust noise emissions, the wearing
of dark visors, the restriction in engine capacity for learners,
the 125bhp limit, the age restriction for unlimited bhp machines
(direct access test), the gas emissions from exhausts, the single
dipped beam headlight when two lights are fitted (what’s that
all about ?) & more recently top speed limiters.
Some of these restrictions have been Government imposed &
others as a gentleman’s agreement between manufacturers (usually
to prevent Governments introducing stricter limits).
Initially I’ll talk about engine output restrictions
& ways of overcoming these (although these mods may make your
machine illegal for use on British roads.
In the late eighties & early nineties the major motorcycle
manufacturers self imposed a 125bhp limit on their machines for
the UK (other European countries got more severe limits). These
limits were achieved in a number of different ways by the manufacturers.
Suzuki, for example, welded restriction discs (like washers) into
the exhaust down pipes of early GSXR1100’s, Yamaha had moulded
in webs in their 1000cc FZR’s inlet rubbers & Kawasaki
had carburettor caps on their ZZR1100’s that prevented the
slides opening fully. All of these methods being relatively easy
to rectify.
Then Triumph came along with their 147bhp Datona 1200 & the
rest followed suit.
During this time bikes were being restricted in their mid
range (usually between 4000 & 5000 rpm) to meet emission levels.
This was usually achieved by clever profiling of the carburettor
needles & as such aftermarket manufacturers produced kits with
re-profiled needles to give us back our mid-range power. In early
893cc Fireblades in particular the improvement in the mid-range
was extremely noticeable.
As bikes became more powerful manufacturers began to restrict
the power a little in the lower gears
to make them easier to ride & later on with fuel-injected bikes
appearing, all sorts of restrictions to midrange power & power
in certain gears was achievable. Also, for the very fast machines
top speed limiters were introduced. Most of these restrictions can
be removed by means of clever little electrical gadgets, these being
readily available from after market suppliers & tuning shops.
At least one manufacturer now, as I understand it, has a two
position switch to give different power options on one of their
bikes. One of these positions being full power & the other for
less power but giving the benefit of a softer power delivery combined
with improved fuel consumption (for when you just want to ride normally).
At last the rider has a choice – now that’s more like
it !
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