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1/10 Scale Electric Rally/Touring Car:

Yokomo YR-4 M2 (Radio Controlled Model Review)


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History, Info (and How To Set-up Tips) for the Yokomo YR-4 M2:


  Introduced by Team Yokomo circa 1997, the 4WD YR4 M2 Super Competition Touring Car kit, was based on the car driven by Josh Kyrul to win the 1997 ROAR Carpet On-Road National Championship.

  The model is belt driven, on a double deck carbon fiber chassis, with adjustable flex, sliding battery tray, ball differentials, coil spring over oil filled dampers, universal joint drive-shafts and a full set of ball bearings.

Yokomo YR-4 M2 - 1:10 Electric Touring Car
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  To race the Yokomo YR-4 M2, it must be fine tuned to improve handling, provide responsive steering and give you the grip to cruise around corners at high speed, without slipping off the track. Small adjustments can make a Big difference and our step by step procedure, will guide you to the best Set-up for your individual driving style.

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★ Yokomo YR4-M2 ★
Yokomo YR4-M2

★ Yokomo YR4-M2 Chassis ★
Yokomo YR4-M2 Chassis

★ Yokomo YR4-M2 Chassis ★
Yokomo YR4-M2 Chassis


Buying a Used Yokomo YR-4 M2
Touring Car (and What to look for)


   Buying a used Yokomo YR-4 M2 Electric Touring Car, or any used RC Model, has a number of advantages. It is generally cheaper than new, ready built and may come with a variety of expensive hop-ups already installed. Cheap, pre-loved bargains are always becoming available. However, depending on the age of your purchase, it may need a little tender loving care before you can take it out on the road.

   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 Touring Car you may discover can easily be fixed.

Dampers
   When you receive your used Yokomo Touring 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.

   If the body shell of your Yokomo YR-4 M2 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 YR-4 M2 model, fit an under guard to stop dirt and gravel entering the chassis.

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 YR-4 M2 Touring Car model at a competitive level, I would also recommend you obtain and fit titanium pivot shafts, turnbuckles, tie rods and steering rods.

   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.

Spur Gears
   Gears are a weakness on all Touring 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.

   Ball joints always cause problems. For top level Electric Touring 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.

Servo Gears
   The YR-4 M2 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.

   If body roll on your Yokomo YR-4 M2 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.

Ball Bearings
   If your used Yokomo Touring 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 YR-4 M2 model and good racing.


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Manufacturers and Brands Catalogued and Listed 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 Model 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.


















Hints and Tips

Sway Bars

   On most forms of RC model cars, Sway Bars, also referred to as Stabilizers, Torsion Bars, or more commonly in some parts as Anti Roll Bars, are often nothing more than a short length of spring steel, clamped to the chassis or sometimes the gearbox of the car, extending out to the lower wishbones direct or connected to the wishbones using short adjustable or fixed length links and ball joints, depending on their position.

   The principal behind the Sway Bar is simple. As the car enters a corner, weight is transferred to the outside wheels, the chassis rolls due to inertia and the suspension dips and grip on the inside wheels is reduced. In an effort to counter this dipping effect and transfer some grip back to the inside wheels to improve traction as you exit the corner, the sway bars transfer the dip of the outside, to pull down the inside wishbones, improving grip on the outside wheels and improving overall stability.

   Sounds complicated I know, but for some tracks sway bars can be a useful tool when you have exhausted all other options to correct your handling problems.

   Tuning your Sway Bars is quite easy. Some manufacturers do offer colour coded tuning sets with varying thicknesses of spring steel wire, but the best way is to change the position the bar is attached to the wishbone, or on some variations you have the option of positioning the link on the Sway Bar itself. By simply moving a small collet clamped along the short length of the bar. Closer to the central pivot point reduces the leverage of the bar and effectively increasing its resistance, further away from the pivot point reducing resistance. More fine tuning can be achieved by adjusting the length of the turnbuckle link (if available) to pre load the bar.

   Personally, before I ever installed any sway bars I would always try changing damper tuning springs and oil viscosity settings, especially if the track was uneven and bumpy, in which case the effectiveness of the bars was minimal if at all.

   For those more into Drifting, Sway Bars can be an easy way to fine tune your car. A single turn on the turnbuckle links can be a way to simply increase or decrease wheel traction that minute amount you need to get the perfect balance.

   For more on how to use Sway Bars check out our Set-up tips page linked below.

For More Setup Information check out my Hints and Tips page.







Hints and Tips


Electric Motors for RC Models

Brushless Motor Basics

   Choosing the right Brushless motor for your needs can be a daunting task for those new to Radio Controlled Models. If you have a local club perhaps you could ask some of the more experienced members for their advice, but a little basic knowledge about the subject, so you know what questions to ask is always useful.

   All Brushless motors are rated by Kilovolts (KV) and is an indication of the revs per minute (RPM) that particular Motor can attain running freely, under no load conditions, per Volt of input.

   For Example: To calculate the Maximum RPM of a Motor listed at 4000 KV, connected to a 7.4 Volt Battery, simply multiply the two: 4000 x 7.4 = 29600 RPM.

   The two main types of Brushless Motors used in RC are Sensored and a Sensorless Motors.
   Sensored Motors can be connected directly using s cable, to the Electronic Speed Controller (ESC). The ESC is then able to monitor the performance of the Motor and regulate Current output, to attain smooth, controlled acceleration. Advance and Retard timing is made automatically by the ERSC to change torque when exiting corners and give you more RPM for long straights.

   Sensorless Motors can only be set manually for Advance and Retard timing and once that setting is made you have to stick with it. For obvious reasons, Sensorless motors are cheaper to buy than the Sensored type: Ideal if you just want to bash around in the back yard, but not so much if you are serious about your racing.

   Brushless Motors, need a reasonable amount of maintenance if they are to remain competitive. For top level racing I recommend you strip, clean and re-oil the bearings every 2 or 3 meetings (Check out our "get the best from your bearings" section).
   Gearing your motor correctly for any given track is always important. (Check out my Gearing tips on the Pinions Section of this site) A cool motor is an efficient motor. As your motor heats up towards the end of a race, it will loose efficiency. Gearing correctly can avoid this problem to some degree and simply following my simple guidelines, described in the aforementioned article can help you not only keep your motor running efficiently, but help you stay in front of your opposition.

   One last tip .. When re-building your Brushless Motor, to safely replace the Rotor, use a rolled up piece of paper and place it into the Can. This will protect your rotor against damage. Then carefully remove the paper before replacing the endbell.

For More Setup Information check out my Hints and Tips page.










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