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Tech Tips
XX4
Less Slippage
The slipper on the XX-4 can be tough to get tight enough on certian track conditions. Under high-traction, bumpy conditions the plastic spacers that are located next to the bearing in the slipper assembely can take a set and keep the slipper from neing fully tightened. The result is usually a melted belt pulley due to the excess slipper heat caused by the slipper constantly slipping. A simple solution is to add two thin 3/16" shims btween the spacers and the bearing on the slipper assembly. This will allow the slipper nut to fully tighten the slipper. The tighter adjustment will keep the slipper from slipping ecessively and help prevent the belt pulley from melting.
Lock It Up
The one-way/clicker assembly on the xx-4 is very cool! It allows the front braking force to be adjusted anywhere from virtually non-existent to fairly heavy. If you'd like to have even stronger front brakes, there is a way to increase front braking force even more. To do so, remove the small adjstment nut from the one way/clicker assemebly. Next, Remove the spring spacer and clicker sping. Carefully ( you don't want to drop it inside and have to take your car apart) place a rear axle spacer over the shaft and align it so that the spacer is centered on the shaft around the portion with the flat section. Place th e spring spacer over the shaft, next to the axle space and tighten the adjustment nut against the spring spacer. The one-way/clicker should now be locked in place. The result is full-time 4wd and full braking force to both the front and rear wheels.
Insulated Battery Packs
It is very important that the chassis of the XX4 does not come into contack with any bare wires, batrtery bars, or exposed edges of any cell. Any such contact can cause electric current to flow through the classis th other parts of the car. This is especially true with a grafite chassis. The result can be radio interference, or even a shorted battery pack. To help prevent these problems, run a small strip of electric tape or chassis protective tape along both sides of the foam battery pad on the XX-4 chassis. This will keep the exposed portion of the cells, where the heat shrink usually wears or cracks away, from touching the chassis. Where you're at it, apply a small piece of tape under the motor. This will prevent the tab on the endbell from touching the chassis when a large pinion gear is used and the motor is moved closer to the chassis.
Easy Gear Mesh
The gear mesh on the XX-4 is easy to set. Simply install the motor, leaving the screws in the motor clamp loose. Loooking at the motor from the left side, rotate it clockwise as far as possible. With the car sitting on a car stand or something similar so that all four tires are off the ground, rotate the front tires backwards. The gear mesh should sound horrible. Now, simply rotate the motor counter-closewise slightly. Rotate the front tires backwards one more time. The gear mesh should be a little quieter. Continue this process until the gear mesh is quiet while turning the tires. Then, go ahead and tighten the screws in the motor mount clamp. As a final check, remove the gear mesh access plug and check to be sure that there is a little backlash between the spur gear and pinion gear.
GTX
Whoah! Stop!
If you'd like to increase the brakes on your GTX gas truck, there is a quick, simple trick to make the brakes much stronger. This is especially useful if your GTX is being run mostly on the street or asphalt. The next time you replace the brake pad on the brake arm, put one on the bottom of the tab as the instruction indicate. Then, put an additional piece of brake pad material near the top or the brake arm. This will make the braking action much stronger. In fact, the brakes will be so strong that you may need to reajust the collar at the end of the brake linkage rod to reduce the spring tension. If the brakes are still too strong, simply turn the end point adjustment down the transmitter. it's not uncommon for the brake throw to be at about 60%-70% with the dual-pad brakes installed.
Sealed To Perfection
When operating gas powered trucks, the engines can appear to be very finicky at times. The simplest fix for many of the problems with an inconsistent running gas engine is to simply seal all of the areas on the engine that could potentially leak air. Most, if noot all of these areas are located on the caruretor. To seal the carburetor, you will need a good quality, high temperature silicone sealent. Such a sealent can be found easily at any auto parts store. Start by removing the carbueretor and applying sealent around the neck of the carburetor. When replacing the carburetor be extra careful not to allow any of the sealent to enter into the engine or carburetor. Next, remove the nuts holding the fuel fittings and needle valve housing to the carburetor. There should have been a wrench or two included with your engine that will fit these nuts. Apply silicone sealent to these fittings before re-attaching them. Again, it is very important to allow the sealent to enter an area that could cause a blockage of fuel flow in the carburetor.Once a carburetor has been properly sealed, it can operate much more consistently and be much easier to tune in. If you check any of the factory racer's trucks you will find that every one of their carburetors are sealed.
XX(cr) XXT(cr)
Seal It Up
If you are using one of Team Losi's lightweight aluminum top staft/gear assemblies, and run your vehicle in an area that is sandy, you should read the following instructions for sealing your transmittion housing. Enen if you arnt using the aluminum top shaft, but run in extremely sandy conditions you might want to give this a try. Once you have rebuilt and cleaned out the transmittion housing, lightly lube the gears in the transmittion. Team Losi's Teflon™ thrust bearing/assembly grease should be used. remember, only a little lube is necessery. After you have lubed the gears, run a thin bead of diff grease along the entire edge on the left transmission housing in the area where the left housig touches the right housing. Running the grease along this edge will help to form a "seal" once the transmission halves are bolted together. Once the diff grease has been applied, bolt the transmission halves together and wipe off any excess grease. Not only will these easy steps help to seal the transmission, they will also make the transmission quieter and more efficient.
Cut Down On Interference
Radio interference with electric-powered cars and trucks can sometimes cause racers to scratch their heads, wondering what exact;y is causing the problem. You're already aware of most of the common causes, such as: Loose wire connections, no capacitators on the motor, loose crystal, cut antenna wire, someone else on the same frequency, etc. There is one other source that is almost always overlooked- the chassis. That's right, the chassis can actually cause radio interference. While this is true for a standard Stiffezel chassis, the risk of interference being caused by the chassis has increased when a graphite chassis is used. The material used to produce the chassis is conductive- meaning that it can pass current. The interference is caused by current from the battery, in one way or another, passing through the chassis. There are a couple of simple precautionary measures that can be taken to help prevent radio interference caused by the chassis. Most importantly, you should ensure that none of the cells in any of your battery packs has torn, or worn-out shrink wrap. If an exposed side of a cell comes into contact with the chassis, the current will be passed through the chassis- likely resulting in radio interference. If yoou have a cell with an exposed side, wrap it with tape or clear heat-shrink to insulate it from the chassis. Another area of concern can be the rear portion of the chassis that the battery pack fits under. If thick battery bars are used, they can touch the chassis. This contact will again cause current to be passed throught the chassis. This potential problem can be handled by simply applying a piece of tape, or a sticker to both sides(inside) of the rear portion of the chassis. The sticker will act as an insulation and keep current from passing through the chassis.
Removing Steering Bushings
If you have ever trieed to remove the steering bushing on your XX or XXT you know how tough this can be. Here is a simple way to get them out. Find a 4-40 cap-head screm of and lengh. Slowly start to thread the scrrew into the bushing. Be sure to apply a slight amount of presure to the screm so that the threads will start into the bushing. Once the screw has theaded into the bushing (it doesn't take much) you should be able to pull the screw out along with the bushing. It is only recommended to use this method of removing the bushing if you plan too replace the bushings with new bushings or bearings. Reusing a bushing that you have removed with this method may cause the steering to bind slightly.
Easy Strap Adjustment
The hook and loop-type battery straps supplied with thw XX and XXT kits make installing the batteries quick and easy. There is a way to make the tightening of these straps easier. When the strap is installed through the slots in the chassis, make sure that the "fuzzy" side of the strap faces up. This way, when the strap is pulled tight, it will be able to slide in the slot. If the "rough" side of the strap is facing up, the strap will not slide very easily in the slots, making it difficult to tighten the strap against the battery pack.