No more guessing
in the morning or in the starting line. Aircraft quality design
and materials with tight tolerances that allow this valuable investment
to perform in top condition all the time. MasterTune has been flow-tested
in England by Mike Hemingway of UK Racing Spares Ltd., a company
dedicated to the preparation of Aprilia Grand Prix motorcycles.
plug and main jet come out of the carburetor. A new oversized, re-designed
jet goes in, and the new plug is installed. As simple as that.
Follow the initial
set-up instructions carefully and
concentrate on driving the kart, the MasterTune will
help you adjust the main jet while you
drive. Start your first practice session rather rich, and lean it
down to optimum following the EGT temperature rise. Read the spark
plug as always, to confirm the EGT reading and enjoy the drive, you
will never need another main jet change,
The whole assembly
takes ½" on the bottom of the carburetor, so make sure
you have the proper clearance. The flexible shaft can be installed
with the knob near the spark plug, if you
have a different requirement, the shaft can be cut at any length.
adjustment is very precise, the range is 3-½ turns on the
needle from fully closed to fully open, which represents a 254 jet
in a 39mm Dellorto carburetor. The 5 to 1 reduction gear allows
the knob to turn 16 times, and it has four clicks per turn, each
click representing approximately one half of a number of a jet size.
In the morning when you practice,
the air is good, cooler and has
more density, so the knob will be turn
to rich, and the EGT temperature monitored. At race time it is
usually afternoon, the air is less dense and warmer, so the knob
will be leaned. Even in your parade lap(s) when you are not
flat-out, you could lean it a bit to avoid flooding the engine and
eventually fouling a plug , and open it up to the normal setting as
you accelerate across the green flag.
race weekend you should start from scratch, meaning turn the needle
in until it bottoms, and open 7 turns. This should set the carburetor
rich for almost every race track out there.
Racer Investment: $379.00
plus $19.00 for shipping and handling within USA .
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