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if you oil the standard clutch bearings, the lubricant can migrate into the clutch. If lubricant comes into contact with the clutch it
will slip and not function properly. For this reason it is also important that you never add oil to the clutch bearings.
If you should ever clean your truck with Armor-All, or a similar cleaner, be careful not to allow any cleaner to enter the clutch
parts or the fuel tank. If the cleaner enters the clutch parts, the clutch will slip. If the cleaner enters the fuel tank, the engine will
run very poorly.
THE BRAKE PAD on your GTX should be inspected after every 2-3 hours of running. When the pad wears down to the
same height as the alignment tab, the pad should be replaced. To replace the pad, remove the old pad with a sharp hobby knife.
Be very careful when handling any sharp hobby knife. Start to cut the pad off of the brake arm from the side near the hinge pin
hole. Be careful not to cut the alignment tab off of the brake arm. This tab serves as both an alignment tab as well as a wear
indicator. Attach a new pad in accordance with the instructions.
THE PRESSURE LINE can be removed from the tuned pipe. Doing this will change the setup of the fuel system to run
without a pressurized fuel tank. At the time of the printing of this manual we had just started testing this. The results thus far have
been very encouraging. We have noticed a better idle for a longer period of time. We have also noticed a better, more consistent
throttle response running without pressure. The manual was written to use pressure only because we haven't had the opportu-
nity to test a non-pressurized tank in different temperatures or altitudes. Running without pressure may not work in all climates.
It's too early for us to say at this point.
If you would like to try to run without pressure yourself, simply remove the pressure line fuel tubing from the tuned pipe.
Route the piece of fuel line back to the top of the rubber header where it attaches to the tuned pipe. Run a small tie strap around
the tie strap holding the tuned pipe to the header and use the small tie strap to secure the fuel tubing to the top of the header. Do
not tighten the tie strap too much. The fuel tubing can't be pinched or plugged up. The hole in the tuned pipe needs to be
plugged. This can be done with a short piece of fuel tubing with a screw inserted in the end of it.
Initially, you will probably notice that the engine will need to be readjusted. We have found the engines a little easier to tune
without pressure though.
THE GEAR BOX, or transmission, is the heart of every race car. The GTX is no exception. Although the GTX transmission
is very efficient, there are certain adjustments that are necessary for top performance. The differential is the most important.
Several greases were tested for use in the differential and the one that we found to work the best is included in the kit. This grease
protects the moving parts extremely well, while at the same time allowing the diff to operate smoothly. Since this differential is
designed to be "self aligning", it is extremely important to take your time while assembling it to make sure that all of the parts are
properly seated into the correct locations.
ADJUSTING THE DIFFERENTIAL This may be a little complicated at first. If you try to do this as you read it, the procedure
should be fairly simple. Tighten the slipper nut all the way down. Now, with the wheels installed, and the tires glued in place, hold
the right rear tire in your right hand. While holding the tire, place your index finger and thumb over the spur gear. Now try to turn
the left rear tire while holding the right rear tire and the spur gear. It should be
VERY difficult to turn the left rear tire. If it turns
easily, the diff is too loose. Tighten it by lining up the slot in the diff screw with the slot in the outdrive and placing the small allen
wrench through both slots. Now
slowly
turn the right rear tire clockwise about 1/8 turn. As long as the diff screw was held in
place with the allen wrench, you have just tightened your diff. Pretty easy, huh? Check the adjustment and continue tightening
the diff, a little at a time, until the left rear tire can't be turned easilywhile holding the spur gear and the right rear tire. Be careful
no to tighten the difftoo much! Once the diff is adjusted, it should still operate freely and feel smooth. If the diff screw starts to get
tight before the diff is close to being adjusted properly, the diff should be disassembled and checked for proper assembly.
Once your diff has been adjusted by hand, start your truck and place it on an asphalt area. Give the truck full throttle from
a stop. The diff should not slip. If it does, tighten the diff slightly until it no longer slips.
Remember! The diff was not designed to operate as a slipper. The truck should never be run while the diff is slipping. Doing
so can damage the diff balls and drive rings. Always make sure that the slipper will slip before the differential!
If your diff becomes "gritty" feeling, it should be rebuilt. Disassembling, cleaning, andre-lubricating the parts in accordance
with the instructions will usually be sufficient. The carbide diff balls that come in the kit should rarely need replacing. If, after
cleaning, the diff still feels "gritty" the following parts should be replaced in the order listed: Differential washers #A-3070, thrust
bearing assembly #A-3071, carbide diff balls #A-6951. When rebuilding your diff it's a good idea to always replace the lock nut.
This will help keep the diff from loosening as you continue to drive your GTX.
SLIPPER ADJUSTMENTS should be made after the diff is properly adjusted. The slipper setting that the manual had you
assemble your truck with should be reasonably close to correct. If you have just adjusted you diff, and the slipper nut is
tightened all the way, adjust you slipper back to its original adjustment by loosening the lock nut one full turn (360° x 1}.
CHANGING THE GEARS on your GTX is a very simple process. The GTX has been designed with a stationary engine
mount. This helps to strengthen the chassis and reduce flex. The stationary mount also eliminates the need to readjust throttle
linkages when changing the gears. There are several different clutch bell/spur gear sets available for the GTX truck. When
changing to a'different size gear, both the clutch bell and spur gear need to be changed. By changing both gears the gear mesh
remains the same, eliminating the need to move the engine.
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