|
NEEDLE JET (Emulsion Tube) and NEEDLE JET CAPS:
Many newer bikes have very flat power and fuel delivery
curves when used with the stock exhaust and air-box. When
aftermarket pipes are used, the power curve is usually not
flat. You find the need to lean out for low speed and richen
up for top end; or leaner on the top end and richer at the
low speed. In order to achieve full function and driveability,
Dynojet develops shrouds or cap style nozzles for adjusting
the upper or lower top end. They also have an effect similar
to fuel injection by breaking up the fuel as it enters the
air stream.
FUEL NEEDLE:
The design of the needle is where Dynojet spends most of
its R&D time. The needle is designed to give the correct
amount of fuel throughout the mid-range and is also designed
to allow adjustment from groove 1 to groove 6 with little
or no effect below 3000 R.P.M.; then with the correct end
dimensions, the needle will have little effect on the main
jet regardless of needle position. This isolates all circuits
from each other and ensures easy set-up of the midrange
and driveability.
MAIN AIR JET:
This jet allows air into the emulsion tube to mix
with fuel being drawn up from the float bowl. It controls
the amount of fuel which can be pulled from the float
bowl into the venturi. The larger the size of the main
air jet, the more air you get and less fuel. The smaller
the main air jet, the more fuel you get and less air.
Dynojet alters this only to achieve the flattest possible
fuel delivery curve.
PILOT CIRCUIT:
This controls 100% of the engine idle and 25% of the
transition onto the needle. Dynojet has found that the
engine will idle with the standard pilot jet, with or
without the air-box and with the slides and needles
removed from the carburetors; therefore we never change
the pilot jet. Doing so is proof that you are not using
the other circuits correctly. Idle and off idle is controlled
by the mixture screws and the float level which have
the most positive effect below 4000 R.P.M. On some models
the pilot air jet is changed to provide optimum fuel
economy. Correct balancing of the carburetors also ensures
a smooth idle. |
|
MAIN JET:
We develop our main jets to correctly serve two functions;
static load and dynamic load. The static load is the fuel
received through the main jet in the upper gears, where
the tachometer is moving very slow. The dynamic fueling
portion of the main jet is the amount of fuel received from
the jet in the mid-range potion of the power. For example,
you have a GSXR1100 G,H with #130 main jets. You then install
#125 mains. After running the bike you notice the top end
has improved but the mid-range doesn't pull as well. You
then install #135 mains and you notice the mid-range is
great but the top end is slower. This is a common compromise
when using stock main jets and needles. If you install Dynojet
130 mains, you would get the mid-range power of the #135
and the good top end of the #125. This is because the Dynojet
main has a venturi design more consistent to the engine's
needs.
|
