• DIY Kydex bumper

  • I’ve been looking for white bumpers for my Yokomo and RC10s after I saw this picture on time tunnel.


    got nothing. but I got a Kydex sheet today from my friend Aaron. it’s the place we got the sheet from


    it’s 1/8″ sheet which has the same thickness with the original yokomo material.

    the part # is 8650K113
    white, 1/8″ thick, 12″ x 12″, and cool

    they usually use a electric oven for DIY kydex job, but I put it in a boiling water for a minute or so. and put it on the original bumper then pressed.
    it was quite easy to bend. also the sawing was, but the trimming job wasn’t to me. but I noticed I got wrong idea about bending. all the bumpers I made were slightly crooked and need to be re-bent. the bent material goes back to the original flat shape so easy in a boiling water.

    the bumpers on 834B, 870C, and, Works 91/93 are slightly different but, basically same. and, you can make more than 12 bumpers with one 12″ x 12″ sheet

    it works for RC10 as well

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  • en Yokomo MR-4BX

  • MR-4BX series has been produced for only a couple of years. the first version came at ’06 and replaced with B-Max4 which was different from previous yoke buggies at ’08.

    MR-4BX series is like the last blood of traditional Yokomo to me. and I see the same blood on Jconcepts BJ4. 

    a few prototypes on Japanese magazines were not far from MX-4 YMP until 2004. they put a slipper clutch, moved the motor mount forward, put B4 rear arms and losi style steering knuckles, and so on.. through early ’06
    my friend who has been working with Yokomo and other japanese rc companies told me their CNC machine was never stopped for a couple of years to make new prototype parts. I know it never stopped before MR-4BX. but more than a few MR-4BX prototypes have spotted on Yatabe arena for years.

    I have managed to get a nicely used Worlds edition last month. and took some pics with my factory edition. they both came at ’07.


    the differences between them are main chassis, F/R shock towers, top deck(s), steering, rear bulkhead, and a few misc parts

    Front End


    MR-4BX Worlds came with a new camber mount which allows only the longest upper rod setup. also the steering is different than previous 2 versions

    this new camber mount can be installed on older versions as well

    the original and Factory edition’s front tower provide 6 points of upper rod mount position. the tower is compatible with the original through Worlds. and the inside position provides pretty much same result as Worlds’ front camber mount




    the steerings are quite different. I hope I can feel the difference while I’m running this Worlds edition. but, didn’t have a chance so far.



    this steering was introduced with MX-4. prototype MX-4 still had older servo saver. and the first time I saw this was in MX-4 kit.

    but the difference is the angle. this steering system on MR-4BX is tilted for better handling.


    this 2 piece structure was came from the prototype and applied to the production models through the 1st and Factory edition. but Worlds edition came with 1 piece chassis


    MR-4BX Worlds came with this 1 piece chassis with 2 extra holes for new steering system. please ignore the stainless screws on the Factory chassis. I’d go back to the black steel screws.


    Top Deck

    the top deck, now it covers the rear belt. and new camber mount is here

    Factory edition had 2 piece top deck like the original version. but the rear piece was improved that older one has clearance problem with the belt

    the rear top deck from the ’06 original version
    Rear Shock Mounting

    there were a few guys tried this before Worlds edition came. the shocks were moved to the back end of the car.

    also they put a camber mount like the front end

    the original and Factory edition had same suspension geometry. the shocks can be moved to the back end with this stock mount plus a few tricks

    the new aluminum part which holds the the shock tower is changed along with new bulkhead and camber mount




    related links


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  • en Tamiya Tamtech Buggy Champ

  • I’m running this small version of Buggy Champ – Rough Rider for years. yes, it’s small and cannot run on the bumpy tracks.

    and I watched it’s not bad on the the rally circuit where I’m running my old RC10 and 834B runners.

    I started from finding a better motor for this 1/16 Buggy Champ. sport-tuned motor from tamiya was the most easy to find. but it turned out not much better than the stock motor.
    they released a better sport-tuned SPT recently. and, I was told it was good. I’m thinking getting one at some point. 

    this tamtech champ came with the plastic spring dampers. buggy champ runs like tamiya grasshopper with the stock shocks. actually it runs better than grasshopper.

    google found me Losi Mini-T shocks weeks or months ago. an I’m running with the shocks. losi shocks turned this tiny champ into a racer.

    Losi shocks are slightly shorter than stock ones. and this length is better on the tracks and my living room.
    Losi front shocks have almost twice bigger stroke with a dead center. and, this simple trick with shrink tube is working great. 
    then I came back to the motor.
    a friened who is an expert on the small motors told me to find “Speed 300 6V” motor from Graupner or GWS. 
    Speed 300 on ebay.de
    ElectricFly  T-370
    but the shipping charge for one single motor was overkill. I found this for less than $10 include the postage from somewhere.
    this E-sky 370 motor is cheap and can be found everywhere. it has this 1/10 style endbell as you can see. the size is identical to the stock 370 motor.
    the torque and speed are great for the scale. and it turned out this motor needs too much juice for the size. I might need more or better batteries.
    I ran with this setup for a while, then I went to Tamtech SPT motor and new shell. SPT is much better than older sport tuned motor in every way. I have brushless in my mind too. but the price is an issue for me.
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  • en 2.2″ front wheels and axles for RC10

  • I got myself this front axle mod idea from rc10talk.com forum when I wanted to put Yokomo 2.2″ wheels on my RC10 runners a couple of years ago. Associated #7222 axles are everything actually. there are not much left to do except for getting the axles if you want to use B4 or JC rulux wheels


    longer axle on the right side is ASC7222 that makes you can use none-offset wheels like B4’s, Yoke 4WD’s, and more


    Yokomo made TH-1 wheel adapters for RC10. early TH-1 came with front adapters as well. but later TH-1 didn’t

    I had managed to get a set of front hubs. but needed more. and got another set from a trick with Ultima hubs.



    got this after I trimmed the each side of Ultima front hub from TH-8 package above. the diameter is “slightly” larger for 3/16″ bearings. but the tiny play (gap) was fixed with Loctite. then I’v been using the hubs without a issue




    RC10 axles and wheels

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  • YZ-834B prototype images

  • got the pictures from my RC buddy yesterday. unfortunately, I didn’t get any information of the source where the pictures came from

    Magazine: Model Channel
    Issue: May, 1983
    Title: RC Car – New Kit(s) Info








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  • 2 cents tip for searching japanese web sites

  • use this list for searching yahoo japan auctions and other japanese sites
    try http://auctions.yahoo.co.jp/
    and there are lots of english service like this one

    Yokomo ヨコモ
    Dog Fighter ドッグ ファイタ
    Prototype プロトタイプ (or プロト)
    Hot laps ホットラップス
    Front フロント
    Rear リア
    Bulkhead バルクヘッド
    Universal ニバーサル
    Axle(s) アクスル
    Tires(s) タイヤ
    Wheel(s) ホイール (or ホイル)
    Decal デカル (or デカール)
    Body ボディ
    Motor  モータ
    Motor Mount モーターマウント
    Works ワークス
    Vintage  ヴィンテージ (or ビンテージ)
    Chassis シャーシ

    AYK あおやぎ
    Kyosho 京商
    Tamiya タミヤ

    and you can use Wikipedia for this purpose
    let’s see an example
    see Languages menu at the left bottom. you can see Japanese as well

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  • Kyosho Cactus

  • This one has a unique and simple tranny. there is nothing but a set of helical gear in the gear box. one of the interesting parts is the tires. they are sealed and have the air inside like 1:1 car tire tubes.
    it came from ’79 or ’80 according to this.http://www.monstertruckfever.se/cactus.html. but I cannot remember exactly. it was far from my interest back in the days. anyway it’s beautiful











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  • RC10 box pictures

  • RC10 ’94 Worlds Japanese version – 1994


    RC10 Graphite Team Car – 1990

    RC10 Team Car – 1990

    RC10 CE – 1992 version

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  • RC10 and 834B running pics

  • keep them running!







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  • Yokomo 2.2″ wheels from JC Racing Products

  • UK company JC Racing Products (http://www.jcracingproducts.co.uk/) makes 2.2″ wheels for Yokomo wheel hub. and they sell them on ebay
    KEIL sold the wheels with his brand name at 90’s as far as I remember

    I just got white and fluorescent yellow dish wheels from them. I’m not sure when I can go to the track with the wheels. winter is cold here. and the indoor circuit in my town closed forever. here are some pics

    Yokomo 2.2″ wheels have raised 8 ribs inside. and JC wheels got only 5 ones which are almost flat and thicker

    the wheels were sold under KEIL brand at 90’s. and I think that means the wheels are strong enough. actually they are softer then Yokomo’s and don’t seem to be broken


    the edges need to be trimmed before gluing

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  • Yokomo YZ-10 runner

  • I went back to older ’94 chassis from ’95 Worlds Spec (Pavidis edition). ’cause the original chassis looked better for Lipo setup. and it is

    ’95 chassis is still great for looking and was for running. but   we don’t need the weight saving holes anymore with Lipo setup. even the chassis is not strong enough for Lipo + brushless

    older epoxy topdeck always worked for me. so, I went back to it


    YZ-10 with Lipo seup


    and more pics with the body.
    the rear wheels came from my ’91 RPM RC10




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  • RC10 axles and wheels

  • the dog bones are identical to B2 and B3 from RC10. B3 should have slightly longer one maybe. but they put same one on the kit. and B4 axle is basically same except for the length and the spacer. the bones too, of course
    from left to right RC10 dogbone axle, RC10 universal, and B2/B3 universal

    #1 with stock 1/4″ axle


    RC10 CVD – 1/4″ axles
    stock #6366 (#6365) hub carrier with 1/4″ x 3/8″ flanged bearings

    there are not much options left with stock 1/4″ axle. they would be Yokomo TH-1 with deep offset wheels

    or, hex adapters from a few manufacturers like HPI

    stock 1/4″ axle with HPI hex adapter
    #7365 (#7358) hub carrier with 3/16″ x 3/8″ bearings


    stock 1/4″ axle with Yokomo TH-1 adapter

    recently found yellow and white wheels for hex hubs from Hong Nor (OFNA).  the wheels are for CRT.5 and work with RC10. and the offset is identical to B2 wheel’s

    Hong Nor (OFNA) TM-49Y yellow (white is TM-49W)
    ZC-835 wheels with Suzuki wheel hubs
    ZC-835 wheels with TH-1
    and the original setup



    #2 with 3/16″ B2/B3 or B4 axles
    there are a few knows tips like this one from rc10talk. and you can find more from the forum. it’s a great site for you and your cars both
    RC10(B2/B3) CVD bones with B4 3/16″ axle and spacer
    I prefer B4 axles than older B2/B3’s. this setup provides more wheels that I can use. even I’m using Yokomo TH-1 with a simple trick
    both axles were made for 8-32 locknut. but the diameters of the selected area are different

    so TH-1 doesn’t fit the axle

    enlarge the hole with step bit or 3/16″ drill bit.
    I tried step bit and the result is pretty good. but I think 4 to 5mm trimming from the inside with 3/16″ drill bit will give the perfect result just like they came from the factory

    then this adapter fits old 1/4″ and newer 3/16″ axles both. actually I did this job a year ago. and still use them on my runners.
    I like this mod ’cause it’s still easy to get TH-1 wheel hubs. and RPM ’91 RC10 doesn’t need the deep offset wheels. the ’91 RC10 in the picture are the same car. I’m using ZC-837 non offset wheels and B4 wheels with it. this RC10 is sharing the pink wheels with YZ-10
    it works with Associated
    #3949, #3950, #3972, #3973, #31032 hex wheel adapters. and with hex type wheels as well.
    ’91 RPM RC10 and modified ’94 Worlds
    gold anodized ’94 Worlds with ZC-835 wheels


    and check the parts from HPI



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  • RC10 chassis weight

  • I was wondering the weight of ’94 worlds chassis and did this a couple of years ago. there were no significant differences between them. but the carbon tub chassis from Fibrelyte weighs only 132g with the bathtub shape


    ’94 Worlds

    B chassis Black
    C chassis Gold
    graphite chassis
    powder coated chassis
    Comcom Fibrelyte chassis – thin version
    later Fibrelyte chassis for truck
    another ’94 chassis I got from japan – unique matte black
    nose plate
    nose plate ’94 worlds
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  • YZ-834B basket case build

  • I posted this on rc10talk forum when I started to build this. it took more than a year just for collecting the parts. and I spent another year for restoring itself

    it was bought from Taiwan at 2007 maybe 2006. I noticed there were only few parts that I could use for my project. it came with broken gear box, missing or wrong dog bones, crushed and damaged axles. broken steering knuckles and more.


    I still have the picture of the parts. every single axle was crushed like this diff out drive

    I had a few parts before I got the 834B. and, had to buy more. the gears and gear boxes from australia, chassis from the states, suspensions from japan. front oneway wheel hubs from australia again. the interesting part was I got some important parts from 3 different people in australia at the same time. recently I built a RPS SE and needed a few more parts. I found them in australia again. thanks to Gary and Jason


    this picture was taken during the restore. I put early chassis and RPS roll bar on my resto. most of the parts I built with were new. and I got tons of garbage. it was like a blues song. I’ll give this story to Elmore James if I meet him in another life

    it took 2 years to the 1st run

    Novak T-1X was crazy powerful

    and got this after I spent another hundreds dollars


    YZ-834B Wonder Dog Fighter with ’83 body















    A friend made me new motor plate. the original one is too weak. even can be bent easily with bare hands. he made 20 maybe 30 pieces and still sells them on ebay. not much left now. so hurry up


    I tried a few different color on the motor plate. red is my favorite

    I wanted to try the box art aluminum arms. and he did it for me. they look great and provide better handling on the track

    and from my another build. thanks to my friend Alan for the parts


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  • RC10 wing wire bending

  • stock RC10 wing wire had .062″ diameter. but yokomo put .078″ wires in japanese version RC10 kits. I tried both and .078″ was better to me. towerhobbies sells 36″ wires. you can make 3 wing wires from 1 piano wire


    the left one was from Yokomo, and the right is stock RC10 wing wire
    and I can barely see the new wire in front of the ruler. it’s 12″ = 30.5cm


    put the 1st mark on the center of 12″ wing wire. and add 2 more 1″ from the center


    then bend it


    almost done


    decide the height of the wing


    slightly bent the legs(?). then the wing tubes hold the wire securely


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  • RC Car Action scans

  • mostly from rc10talk.com



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  • wheels and tires for YZ-834B and 870C

  • already posted this in Korean(한글) on my another blog which I’m building over the last couple of days. and I’m doing this again. I noticed I forgot to put Custom Works wheels in this picture. but I still like this yellow, white, and pinky picture


    the original 1.75″ wheels are yellow and very cool. but they don’t showed up anymore on ebay. 870C wheels are 2.0″ and can be replaced with.
    and, there are few ebay sellers and online hobby shops sell 2.0″ tires

    Losi Rear 2.0 Step-Pin, Silver (2) LOSA7378S


    Tamiya #53059 Wide Stud Spike Tires

    Tamiya wide stud tires work with  870C front and rear wheels both. so it’s not a problem if you only have the front or rear

    870C wheels are deep dish. and the offset is identical to the original yellow wheels

    Front narrow ZC-800
    Front wide ZC-801
    Rear ZC-805


    Yokomo TR-8 was stock rear tires for 870C

    Front TF-8 (S, M, H compound)
    Rear TR-8


    with ZC-800 for front and rear both. and, tamiya wide stud tires


    834B still runs great with 2.2″ wheels and modern tires. rc10talk forum member kustomizerz made this video
    and his chassis are here

    there were a few kind of 2.15″ wheels. ZC-821 front, ZC-822 9mm deep dish front, ZC-825 deep dish rear, ZC-827 with (almost) flat dish
    ebay is the best source for the wheels. 2.15″ ROAR wheels work with modern tires as well.


    2.2″ 30 series wheels ZC-83x

    maybe you can find ZC-837 or ZC-837W 30 series wheels. but they don’t have negative offset. you need to modify the rear wheel hubs if you want to use ZC-827 or ZC-837 wheels
    2.2″ (30 series) Wheels

    Front ZC-831
    Rear ZC-835 (deep dish)
    ROAR size wheels ZC-82x

    2.15″ (ROAR) wheels

    Front ZC-821
    Rear ZC-825 (deep dish)
    ZC-822 2.15″ 9mm deep front wheels (center)
    it’s perfect for 834B and 870C but really hard to find
    with 2.2″ wheels
    Proline Champion tires were great for RC10 and 834B both. and Losi put the tires in their RPS SE kit with Team Losi Racing logo
    a frankenstein with tamiya arm. during leftover build
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  • nice pink wheels from tamiya

  • this Zahhak is based on TRF 201 which is the knockoff of Associated B4. Tech Racing made TRF touring cars for Tamiya. and now Tamiya is copying  BJ4 and B4. what a shame on this!
    you can see tamiya’s own BJ4 from this
    but the wheels themselves are pretty cool. even the pink buggy wheels were kinda trademark of Yokomo
    I was wondering what Zahhak meant. see this if you are
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  • YZ-834B wheel hub mod

  • #1 front wheel hubs
    there are 2 reasons to write on the wheel hubs. the 1st one is they are hard to find. and the other one is for the case you want to run your Wonder Doggie with modern tires. we still have the problem with getting 2.2″ wheels. but let’s get started this topic with ignoring the wheel issue

    she, the shop owner still has tons of 834B parts. but I didn’t see the left side of the front oneway wheel hubs for years

    so, I bought 2 right ones. and tried to pull the oneway bearing out. then put it back. it was quite easy to do with a hammer and 2 thick books. I got a complete pair now


    The original yellow and 870C wheels had deep offset. but later 2.2″ wheels don’t. I tried to exchanged the right and left wheel hubs. and it worked. but wanted better solution to hold the wheels securely

    the wheel hubs for RC10 and kyosho seemed to be worked.
    but, I didn’t try kyosho’s.

    got this after the step bit job with RC10 wheel hub. I didn’t cut the back end. and didn’t have to. it has gone

    it fits like it was made for this






    and after












    #2 rear wheel hubs
    it’s more simple than the front. the hub was from 870C front

    now my 834B got right thread and look
    and you can see the steering from later Yokomo cars. they are basically same. but work better and easier to find

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  • YZ-834B axles and dogbones

  • Yokomo YZ-834B came with few weak spots like most 80’s RC vehicles had some.I have made the list on wikipedia before. pleas check this http://en.wikipedia.org/wiki/Yokomo_YZ-834B and want to add some pics for someone who still runs this old and nice buggy

    the early alxes had problem with strength. and that made the axles like the right one in he picture. you can improve the strength by DIY heat treament. use your gas stove then watch it until it turns to red. and put it in the water quickly. it worked like the left one
    from left to right – hotdog4 rear axles, rear bones from AYK,
    and front dog bones


    hotdog4’s rear axle could be a good replacement. I’v been using them for years. and I noticed they won’t ever be broken or crushed

    the dogbones were from AYK Race Prep. it’s hard to find now. but it worths to get and run with them

    the length of RC10 and 834B front dog bones are identical. but the diameter of the pins are not. you may use RC10’s if you can’t find the orginal or AYK’s. but you need to trim the pins. maybe the heads as well

    Yz-834b stock front axles


    hardened front axles came with later 834B’s and RPS SE

    stock front axles were not strong neither. it had poor resistance to abrasion. the oneway bearing made worn it out like the alxes in the picture

    Later Wonder Dog and RPS SE came with stronger hardwares include this axle
    I pulled this off my runner which has been racing  for years. it still looks like new

    RPS SE C-2 bag picture from ebay
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