Radio Controlled Models
Share RCScrapyard on Facebook
RCScrapyard Radio Controlled Models
Flags
RCScrapyard.net contains Google AdSense Ads and Amazon Affiliate links, from which we may earn commission. See our Disclosure page for more information.
bar

1/10 Scale Electric Rally/Touring Car:

Yokomo MR4 Rally - Radio Controlled Model



History and Info for the Yokomo MR4 Rally:

  Introduced by Team Yokomo circa 1999, the 4WD MR4 Rally, was basically an MR4-TC with rally tires and a protective sealing under bodyshell.

  A number of kits were available: Basic kits MR4IW - Subaru Impreza WRC, MR4CW - Toyota Corolla WRC and MR4FW - Ford Focus WRC: Kits with 10 lay-shaft and axle Ball Bearings, MR4IWB / MR4CWB / and MR4FWB: And also Deal Kits with full ball bearings, motor and ESC, MR4IWD / MR4CWD / and MR4FWD.

  All Rally model kits were belt driven, on a molded plastic chassis, with ball differentials, coil spring over oil filled dampers, dogbone drive-shafts and bushings or ball bearings, depending on the kit.

Yokomo MR4 Rally - 1:10 Electric WRC Car

▼ Scroll Down for More Images ▼


  To race the Yokomo MR4 Rally, you need to tweak and adjust all you can to give your car improved handling, stability and grip to ease around the curves and keep you on the track. One little setting change can transform your car into a world beater. Just follow our chart to attain the most favourable Set-up to suit your particular needs on any track.








Gas/Nitro Engines Body Shells Radio Transmitters etc Tires Wheels/Rims Electronic Speed Controllers Battery Packs / Chargers Electric Motors















Flags
★ Yokomo MR4-Rally ★
Yokomo MR4-Rally
★ Yokomo MR4-Rally Chassis ★
Yokomo MR4-Rally Chassis
★ Yokomo MR4-Rally Under-Body ★
Yokomo MR4-Rally Under-Body
★ Yokomo MR4-Rally ★
Yokomo MR4-Rally

Buying a Used Yokomo MR4
Rally Car (and What to look for)


   There are essentially three reasons you might want to buy a used Yokomo MR4 Electric Rally Car; you may be a collector, looking to restore and display it; restore and sell for a profit; or simply restore and race an iconic vintage model. Personally, I used to get a buzz out of restoring an old clapped-out model, installing modern day electrics and maybe a few hop-ups, then showing the gang at our local club, just how competitive those old models could still be.

   Cheap, pre-loved bargain models, parts and spares are always coming up for sale, but once you have made your purchase, the one thing you will always need, is an instruction manual. If not supplied with your purchase, they can often be downloaded from the Yokomo website, or purchased separately on eBay. With an instruction manual, any problems with your model Rally Car you may discover, can easily be fixed.

Make a General Visual Inspection

Dampers
   When you receive your used Yokomo Rally Car, make a general visual inspection of the chassis, front and rear wishbones, suspension shock towers etc, for any broken parts that may need to be replaced. Then, take a screwdriver and box spanner and check each self tapping screw and nut for security, taking care not to over tighten.

   Next, for those Yokomo models with oil filled shock absorbers, remove them from the chassis and dismantle the coil springs. The damper shafts should push in and pull out with a smooth action. If you feel a jolt as you change direction, this means the oil has leaked out and must be topped up. At the same time, change the O-Ring seals to prevent more leakage. Also check the damper shafts for damage. If they are scratched, change them as soon as possible.

Check the Body-Shell

   If the body shell of your Yokomo MR4 is broken, ripped or damaged in any way, this can be easily repaired with rubber solution glue. Also, for added protection and if available for your MR4 model, fit an under guard to stop dirt and gravel entering the chassis.

Drive Shafts and Turnbuckles

Titanium Turnbuckles
   Examine the drive shafts for wear and replace as required. If possible, change them for titanium. The steel shafts wear and bend too easily.

   If you intend to race your MR4 Rally Car model at a competitive level, I would also recommend you obtain and fit titanium pivot shafts, turnbuckles, tie rods and steering rods.

Examine the Drive System

   Drive Belts need checking at regular intervals for wear, tension and damage. If deemed necessary, adjust the tensioning pulley until the belt can be depressed in the centre by no more than around 5mm. If the belt was slack, also examine the drive pulleys for wear. The teeth should provide a well seated fit for the belt teeth and not be rounded on the corners. If the belt teeth do not fit snugly, change the pulleys as soon as possible. For top level racing it may be prudent to replace all belts and pulleys after each race meeting.

Pinions and Spur Gears

Spur Gears
   Gears are a weakness on all Rally Car RC models. Head on collisions can easily damage the gear teeth on nylon and plastic spur gears. Heavy impacts can also loosen the nuts or self tapping screws that hold the Electric Motor in Position, allowing the pinion gear to pull out of mesh slightly and rip the tops off the teeth on your spur gear. To minimise this possibility, fit bolts with locking nuts to the Electric Motor mount and remember to check them for security after every two or three runs.

Don't Neglect the Ball-Joints

   Ball joints always cause problems. For top level Electric Rally Car racing, the plastic ball connectors should be checked and if deemed necessary changed after every meeting. A simple thing like a loose fitting connector popping off could easily end your race, so better safe than sorry.

Steering Servo and Servo-Saver

Servo Gears
   The MR4 steering servo is also prone to damage. In high speed crash situations, the fragile gear teeth of the servo can be broken off, rendering your expensive servo useless, so be sure to obtain a good quality "Servo Saver". Check out my Servo Information article.

Stabilizers

   If body roll on your Yokomo MR4 is a problem, handling can be improved with the use of stabilizers, anti roll or sway bars, stiffer tuning springs and, or, thicker silicone oil in the dampers.

Don't Forget those Bearings

Ball Bearings
   If your used Yokomo Rally Car comes with plastic and sintered brass bushings (ring type bearings), check the shafts that run in them for wear. Dust and grit can get into these bearings and abrade the shafts. Therefore, you should replace them all with shielded ball bearings. If the model has been run with ring type bearings, you may have to change all the axles and driveshafts. For more information, take a look at my article, How to get the best from your Bearings.

   Finally, good luck with your MR4 model and good racing.

▼ Scroll Down for More Articles and Advice ▼

Or, check out our RC Model Car Setup Guide

^ TOP ^












Manufacturers and Brands Catalogued, Listed and Reviewed by RC-Scrapyard.

   At present, the RC Model Manufacturers, Brands and Distributors covered by us are: ABC Hobby, Academy, Acme Racing, Agama Racing, Amewi, Ansmann Racing, ARRMA, Team Associated, Atomic RC, Axial, AYK, Bolink, BSD Racing, Capricorn, Carisma, Carson, Caster Racing, Cen, Corally, Custom Works, Durango, Duratrax, ECX - Electrix, Exceed RC, FG Modellsport, FS-Racing, FTX, Fujimi, Gmade, GS-Racing, Harm, HBX, Helion, Heng Long, Himoto Racing, Hirobo, Hitari, Hobao, Hong-Nor, Hot Bodies, HPI, HSP, Intech, Integy, Jamara, JQ Products, Kawada, Kyosho, Losi, LRP, Maisto, Mardave, Marui, Maverick, MCD Racing, Megatech, Mugen, New Bright, Nichimo, Nikko, Nkok, Ofna, Pro-Pulse, Protech, PTI, RC4WD, Redcat Racing, RJ-Speed, Robitronic, Schumacher, Seben, Serpent, Smartech, Sportwerks, Step-Up, Tamiya, Team-C Racing, Team Magic, Thunder Tiger, Tomy, Top Racing, Traxxas, Trinity, Tyco, Vaterra RC, Venom, VRX Racing, WLToys, X-Factory, Xmods, Xpress, Xray, XTM, Yankee RC, Yokomo, ZD Racing and Zipzaps.

   This is an ongoing project, with new and "lost in time" RC Models and Brands being added as they are found and although most of those listed above have been covered in relative detail, some are still being researched and will be completed in the near future.



















★ Yokomo MR4 Rally Chassis ★
Yokomo MR4 Rally - Chassis





Hints, Tips and Information

Efficient Soldering

   In the sport of Radio Controlled racing, there are a number of things you have to learn to get you up there with the best. One of the most difficult, for those with little practical skill, is the art of Soldering.

   For their 540 silver can motors, Tamiya provide two wires, typically green and yellow, soldered to the endbell, with two bullet connectors to plug into the speed controller. While this is fine for bashing around the back yard, as you advance to a higher level you will soon find just how inefficient this method is.

   Motor wires are best soldered directly to the ESC. That way no energy is lost through high current draw. Some of the top drivers at one time even used to solder their batteries directly to the ESC.

Read the Complete Article  ▶ ▶






Hints, Tips and Information

Choosing the right Tire Inserts

   Once upon a time, all RC model tires were equal - they were all trash. None of the old tires had any kind of internal support, because the hard compound they were made of didn't need it. But that was before the newer soft compounds were developed. These new tires were so soft that if some kind of insert was not used they would just lay flat under the weight of the car. Thus, the new science of tire inserts was born.

Inserts for Off-Road Tires

   The basic soft foam inserts that come with many off-road rubber tires can be in one of two types. They can be basic rings of sponge, or the cheap and nasty strips of sponge. Many of the latest foam inserts now come pre-shaped, but more than often, they will need some work done to them before they are inserted into the tires.

Read the Complete Article  ▶ ▶







RC Models:
Radio
& Motors:
Other
Accessories: