Fuel line is susceptible to pinhole leaks. You cannot see the
hole in the fuel line, but if you see air bubbles in the line
going to the carburetor, replace the fuel line. Another
symptom of a leak in the fuel line is a surging engine. The
properly tuned engine will surge when the air bubbles hit the
carb. It is basically leaning out the mixture.
To keep dirt out of the engine, we recommend that you use
an inline fuel filter on the fuel line running from the fuel tank
to the carburetor. Dirt can get caught in the needle seat and
cause an inconsistent running engine. If you suspect that
some dirt has lodged itself in the carb, remove the needles
and clean the carb with denatured alcohol or fuel. It can help
to use compressed air to blow out the fuel passages as well.
Dirt can get into your carburetor and engine through the air
filter. Ensure that your air cleaner has a good seal to the top
of the carb. Periodically wash the air cleaner foam element
and re-oil the filter. Any air cleaner that has a torn element
or a bad seal should be replaced immediately.
Overheating
One of the worst things you can do to your engine is
overheat it. The oils that lubricate the engine are carried in
the fuel. If your engine is set too lean, there will not be
enough oil in the engine to lubricate the internal parts. This
will cause premature wear in the engine and cause
damage. We have talked about overheating in other parts of
this manual, but we want to stress the proper techniques to
check for overheating. The easiest way of checking the
temperature of the cylinder head is using one of the
available temperature gauges. This will give you a direct
reading of the cylinder head temperature. Do not let the
head temperature exceed 220° Fahrenheit (104° Celsius).
Another way of checking the head temperature is to put a
drop of water on the cylinder head. If it boils away
immediately, the high-speed needle is set too lean. If the
water boils away in 3-5 seconds, the engine is within proper
operating temperatures. If the water boils away longer than
5 seconds, the mixture is set rich which is preferable when
breaking in the engine. Otherwise lean the mixture some
and retest after a minute of running.
2-Speed Shift Point Adjustments:
The shift point on the
2-speed transmission is factory set. You can make adjustments
to the shift point on the 2-speed transmission. When you make
shift point adjustments, it is important that your engine has
already been broken in, is properly tuned, and already at
proper operating temperature.
To adjust the shift point use the following procedure:
1) Warm up the engine (run it for a minute or two) and then
stop the engine (see How to Stop Your Engine on page 15.)
2) Rotate the 2-speed outer housing attached to the smaller
spur gear so that the access hole is up.
3) Rotate the outer housing back and forth until you can see
a small set screw on the inner housing. This set screw does
not go straight down into the inner housing, it is set at an
angle. This is the adjustment screw for the shift point.
4) Insert a 2mm allen wrench into the set screw.
5) To raise the shift point (make it shift later, when the
engine develops more RPM), turn the screw clockwise 1/8
of a turn. Do not overtighten this screw you may damage the
2-speed transmission.
6) To lower the shift point (make it shift earlier) turn the
screw 1/8 of a turn counter clockwise. Do not loosen this
screw too much. The screw could fall out requiring
disassembly of the entire 2-speed to repair.
7) Do not make adjustments more than 1/8 of a turn. After
each adjustment, start the engine and test the shift point.
If you have made adjustments to the shift point and want to
return to the factory setting, it is 5.5 turns out from the point
that the screw will not turn in any more without using
excessive force.
It is possible to have the shift point too far in, in which case
the inner clutch on the 2-speed is locked such that only the
two inner gears (the gears for top speed) will be engaged
during the run and the outer gears (the gears for good
acceleration) will not be engaged at all. It is also possible to
have the shift point too far out, which will mean that you are
only running the acceleration gears. In either case you will
not hear the car shift. Make sure that you listen carefully for
the RPM change of the engine that signifies that the 2-
speed is shifting.
Ride Height:
This refers to the clearance between the
ground and the chassis, both at the front and the back of the
truck. The ride height on the Maximum MT Pro should be
approximately 2-3/8" (60mm). To determine the ride height,
drop the truck from around 6"-12" above flat ground. Drop
the truck, making sure it drops flat. Check where the
suspension arms come to rest. You can adjust ride by
moving the spring adjusters on the shock (which are at the
top of each shock spring) until the appropriate height is
achieved after the drop test.
PERFORMANCE TUNING
17
