TamiyaUSA.com - TRF801XT Building Tips

Tamiya MINI 4D EDUCATIONAL

Home>
TRF801XT Building Tips

The goal of the TRF801XT is to offer features and performance not found on any other Truggy on the market. These features include the unique straight line drive train for maximum efficiency and linked brake system for easy and precise adjustments. In addition, the TRF801XT is equipped with an impressive list of standard features and equipment making it extremely competitive in the 1/8th Nitro Truggy market.

TRF801XT Features:

3mm A7075 hard anodized Duralumin chassis

Machined aluminum shock towers, steering knuckles and engine mounts

Low wear, efficient straight line drive train

Carbon fiber servo plate and upper decks

Sealed radio box

Full ball bearings

Sealed bevel gear differentials

Spiral cut ring and pinion gears

Lock nut captured suspension hinge pins

Universal drive shafts

3 shoe aluminum clutch

15mm Large volume shocks with boots

17mm wheel hubs

Front and rear stabilizers

Turnbuckle brake linkage system

Dual 32mm brakes

High volume air filter

Low profile polycarbonate body

Adjustable turnbuckle linkages

Chassis side guards

High down force wing

150cc fuel tank

	Now featured in all TRF801XT kits is the "Performance Handling Package". This parts package includes: 1013 - Short Suspension arms 1014 - Short Lightweight drive shafts 1012 - Heavy Duty upper shock mounts

In addition to the standard features of the TRF801XT, there are a few Hop-Ups that are recommended and worth incorporating into your build. The following are optional but recommended Hop-Ups for your TRF801XT:
84077 - Titanium Coated Piston Rod (rear) 84076 - Titanium Coated Piston Rod (front) 84040 - Light Weight Center Prop Shafts 84038 - Aluminum Rear Hubs 84036 - Light Weight Chassis 1027 - Light Weight Flywheel 1025 - Light Weight Diff Ring (requires 2 sets) 1024 - Light Weight Wheel Axles (requires 2 sets) 1021 - Light Weight Outdrives (requires 2 sets) 1017 - Light Weight Center Joints 9004255 - TRF801X F Parts (caster blocks) 9400956 - TRF801X Steering Knuckle (left) 9400957 - TRF801X Steering Knuckle (right)

Building Tips

Assembling the TRF801XT is as easy as a Tamiya kit gets. However, like any build, there are tips and tricks to make the build even easier and/or the performance better. The following are simple tips to improve the performance of your TRF801XT.

Differential

	The first step to assemble the differentials is to install the Diff Drive Cup. Before doing this, apply a small amount of high temperature grease to the groove of the Diff Drive Cup. Then coat the black 6mm o-rings with silicone diff fluid prior to installation. This reduces friction when the differential is operating, reducing wear and results in more consistent performance.
Fill the differential with your choice of silicone diff fluid but do not fill it to the top. You must leave some space for the large bevel gear otherwise the fluid will just squeeze out. Note the amount of fluid in the picture and how the areas behind the small bevel gears are filled with fluid.
Before installing the diff gasket, apply a thin coat of silicone diff fluid to both sides of the gasket. This helps to create a better seal when the diff is assembled.
In step 2, the diffs are installed into the cases and shimmed with one 13x0.2mm shim. The kit includes extra and it is strongly recommended to use two shims for each diff. Using two creates a better gear mesh and results in longer gear life.

Steering Knuckles

It has become very popular to use the TRF801X (buggy) steering knuckles and caster blocks on the Truggy because of the increased overall steering this provides. To do this, simply replace the Truggy caster blocks and steering knuckles with the Buggy parts (item numbers listed in the recommended Hop-Up list). Be sure to use thread lock on the 4x10mm screws during assembly.

Chassis

There is additional suspension travel that can be obtained with a simple modification to the chassis. Using a Dremel tool with a grinding stone or sanding drum, grind down the two front down travel tabs as shown in the picture.

Engine Mount Plate

Step 16 includes installation of the engine mount plate. Instead of using the 4x6mm screws, use 4x12mm screws secured with 4mm lock nut. This adds security to the engine mount against vibration and load. You will need four 4x12mm screws (9400791) and four 4mm lock nuts (9400975).

Brakes

To glue the brake pads to the brake calipers, for best results, use contact cement. Super glue will tend to crack and the brake pads will fall off the calipers. The best way to use contact cement to glue the pads is to first apply a thin coat to the brake pad and then a thin coat to the caliper. Let both sit for about 30 minutes. This will allow the contact cement to cure a little and become very sticky. Then carefully align the pad to the caliper and attach the two. The result will be a very secure bond.

The next step is to set the brake calipers. When installing the brake calipers to the center bulk head (A1), use one of the brake rotors to gauge the amount the brake bolt is threaded into the bulk head.

This is done by placing the brake rotor in between the brake pads when tightening the brake bolts. There should be a 1mm gap between each brake bolt and brake caliper. This provides enough free movement to reduce brake drag, yet not too much movement that would make the brakes unresponsive.
The center upper deck has two plastic inserts that the brake cams rotate on (C2). To reduce unwanted free play, glue them in place using super glue.

Shocks

When bolting the piston to the shock shaft, use thread lock in addition to the 2mm lock washer for additional security. After installing the o-rings and plastic shaft guides, use thread lock on the threads of the lower shock cap and securely tighten.

Before threading on the pre-load adjuster (DB6 - BD5), coat the threads with silicone shock fluid to make installation easier.

Shock rebound can be set when the shocks are filled with shock fluid and assembled. For the fastest rebound, the shock shaft should be fully extended when placing the oil seal and shock cap. This is the recommended setting for the front shocks. Compressing the shaft into the shock prior to placing the oil seal and cap will slow the rebound dampening. Due to the high volume of fluid the rear shocks are capable of holding; you must set the shock shaft in about 10mm in order for the rear shocks to operate properly. The length of the exposed rear shock shaft is approximately 40mm fully extended so compress the shock shafts so only 30mm is exposed prior to placing the oil seal and shock cap.

After the damper boots are installed, snip small holes in each boot for air ventilation. This allows the shock to function without the boot falling off from internal air pressure build up. When the shock spring and retainers are installed, the spring retainer should securely capture the shock boot as shown in the picture.

Conclusion

Once you've assembled the areas above, the rest of the build is very straight forward.

For set-up information, here is a base line set-up that works well for most track conditions.

However, to get maximum performance, you will likely need to fine tune the set-up to your specific track and conditions. In the TRF site, there are additional set-ups for reference. Good luck and see you on the podium!