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Röthbauer GmbH

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  1. A few months ago I was going to glue my new front and rear tires to the rims and noticed the glue was dried up! Drove to the nearest hobby shop to get a bottle of glue and noticed a few rare items behind the glass case. I asked if they were for sale or just private display. He said make me an offer and there yours. Ok, 75 USD and to my surprise they agreed? I asked how long have they been there? The young salesperson asked the owner and he said it was included in the sale when they bought and old hobby shop back in the early 90’s. I would have never imagined that you could still find something from the good ole days of early nitro at a local hobby shop. Perhaps I should scout around to a few more places just to see what I might uncover. So, all this time, no one wanted this New in box OPS vintage engine? Seem more fitted for on road 1/8 scale cars like the Associated RC500. It’s brand new and turns over and all parts are in sealed bags. Considering how rare it is to find on eBay I thought it was a pretty cool deal. Even the air filter looks like a real chain saw air filter from the 70’s! It even has a rubber boot to attach to the Nr.394 (9mm) carburetor that has PIRELLI on it, so Italian! OPS 3.5 SPEEDCAR COMPETITION Nr. 8750 (the P in OPS is Picco) The original price tag shows 130 USD (Made in Italy). Not sure if it’s early 80’s as some documents in the box show 1980. Something I did see in an old R/C article was that in 1982/83 IFMAR World Championship the popular engines used were OS, Picco, Cipolla, OPS, ECM and the winning engine was Picco then OPS. A few other items needed was the Original OPS exhaust pipe Nr.890 and the KORF exhaust manifold Nr.101521 sourced from Germany at WMS to connect the rear exhaust port from the OPS 3.5 engine. The goal has been to keep all items added in the same 1983/84 timeframe with +/- 1 year. https://www.mantuamodel.co.uk/images/Documents/OPS_3e5_Speed_SPA.pdf
  2. As the 1/8 scale sector was being squeezed out by 1/10 electric the team at Kyosho were still developing a better buggy. The first differential (adjustable with thrust balls) gear for improved handling installed onto an 1/8 scale to deliver additional traction and stability while proving maximum power to the rear wheels. The die-cast gear box is and improved design from the older circuit series; Fairlady 240Z, originally it was a direct drive, making it difficult to accelerate thru a turn. The Circuit 20 Extra is the final evolution for completion use. My original gear box encountered a high speed crash back in 1984 and that was the main reason it went into the closet as parts were not as easy to obtain. It’s been a long search to find a used in almost new condition gear box. The power of the internet! The enclosed gearbox is kept lubricated with 5cc’s of (transmission) gearbox fluid. I replaced all the ball bearings with new ones and even upgraded the clutch bell end shaft which uses a bronze bushing. I will have to cover the outside with double sided tape to keep the elements out. As we explore more in depth of the many components that make up the ball diff, the thrust balls (smaller ones) I used high pressure black grease and for the larger 6 balls held in place with a ball race guide, I used a quality silicon grease. For adjusting the rear differential gear, tighten the M3 nylon nut which are binding the balls to increase the differential gear effect; for decreasing the effect loosen the nuts. Note: when tightening or loosening the nuts, do it evenly little by little at a time in order to keep the plate parallel.
  3. Preparation for R/C racing Will it still be as fun as it was all those years ago? Can reviving past memories really be as exciting as it was in the way we remember it, or will we be reminded of the frustration that made us put the car in the closet in the first place and ignore it and move on to something different? With the weather now changing for the better it’s now time for us to get out on track and pick up where we left off some 39 years ago! Nervous and excited at the same time is really making me fell young again. Ok, that part can not be 100% true but, I think you get where I’m going with this. We built a track over a year ago and have been training/racing our team drivers for 1/10 scale SPEC 13.5T 2WD buggies & 2WD Short Corse Trucks to get our skill level back when we were the dominant force to be beaten at the various tracks we raced at. It’s been a harder task then what I would have imagined as the new R/C technology has improved in a way that would be unimaginable coming from a racer who competed in the mid 80’s when everything was analog! It’s important to point out its contribution into the transition from modern 1/10 scale to vintage 1/8 scale as parts are rare and expensive, so we hope to be our best when the flag goes down for our first Circuit 20 Vintage 1/8 scale race. Pictures are great but, I decided to make a YouTube channel for posting a few videos of various modern and vintage buggies in action. What it takes to design a race track, organize an event, test, tune and maintain them for off road race usage. The various engines available from the early 80’s should make for some interesting lap time comparisons as we attempt to relive the Kyosho Circuit 20 era. In addition to providing live action video with lap timer for the 540 ft (165 meters) length, 10 turn race course with crossover jump. Vintage R/C Racing https://www.youtube.com/channel/UC2jDcL7PGMhYNX2g9XZiW3g
  4. It’s not often you see reproduction of hop-up’s or after-market upgrades for vintage 1/8 scale Kyosho Circuit 20 series. It’s nice to see we have reproduction bodies, tires and decals to keep the passion going for those who are still dreaming of the vintage experience. While most of the options were provided by Kyosho in the beginning, it wasn’t long before others noticed the rise of the R/C movement and the importance of after-market parts. Popular names like Parma, Thorp, Twinn-K and CRP were onboard from the beginning and would become major players in the development of useful hop-up’s to improve performance or reliability. Trying to find these old vintage parts is a painstaking task that just takes time and luck or a bit of both. One of the most important upgrade for the Racing Baja was the adjustable coil over from CRP (Custom Racing Products) Originally released the CRP 1515 Adjustable coil over suspension (Kyosho) in November 30, 1982. The search is over! No Coast RC Products now makes aluminum shock collars in silver or gold finish and the quality of the parts are impressive! In the photo below the original CRP coil over is on the left and the Reproduction is on the right. You can clearly see how the new aluminum is shinny and reflective giving the Kyosho CB-89 red shock a touch of modern. ALUMINUM SHOCK COLLARS - SILVER - KYOSHO / TEAM ASSOCIATED / DELTA TYPE SHOCKS These are reproductions of the aluminum shock collars that were offered by CRP, Race Prep, Parma and others. Initially intended for use with Kyosho CB-88 / CB-89 style shocks, these were well adopted in early days of off-road racing to the Kyosho / Cox Scorpion platform as well at the Tamiya Rough Rider SRB series of buggies. Later seen on Delta style shocks adapted to the Yokomo YZ-834B Dog Fighter and finally on early Team Associated RC10 vehicles. These style collars were also featured on the original Team Associated RC10 box art picture. Dimension accurate to the original and threaded with correct M3 x 0.5mm metric threads, these collars are appropriate to use in any vintage restoration or new restomod build. CNC machined from 6061-T6 aluminum, the finish is 'raw' like the originals, but capable of being media blasted, anodized or polished.
  5. Power is nothing without control - PIRELLI Racing tires are designed to provide maximum traction so, why would Kyosho have only developed one style of tires for it’s 8 year production run. From the original 1976 Circuit Series up until the end with the last two kits of the Extra Series in 1984. More then 10 different kits all using the same front and rear style tires? What Kyosho did offer were the glue on type (CB-36) square blocks or (CB-86) round tubes to provide a variety of treads. Using these Super Spike or Nylon Spike offer a wide selection of tire combinations to match with the track conditions. Tire accessories are to be glued onto the tire nubs for increased traction on loose dirt. I can not imagine racers in the pits gluing rubber spikes to their tires looking for the best combination at a race. The original medium firm rubber Goodyear / Dunlop tires are very durable for most gravel or grass conditions. Front tires (CB-31) are 1.5” (38mm) wide with 7 ribs to guide thru most terrains, at the rear (352X) are the ultra wide knobby tires with a measured width of 2.28” (58mm). On a positive note there are over five different types of wheels offered along with the ultra rare Magnesium two piece wheels, originally designed for the Land Jump 4D. For the Circuit Series part numbers are: CB-102 (Graupner 4984/41) - front magnesium rims and CB-103 (Graupner 4984/42) - rear magnesium rims. Not until 1985 did Kyosho release a new set of front and rear style tires, Sand Super for the (Nr. 3048) Impacta / Mint Las Vegas (Nr. 3049) which are better for road holding and rear wheel traction suited for race tracks, a direct fitment to the circuit series wheels. Front (KC-28) tires are reduced to 5 ribs with a deeper rib grove to improve front steering and grip, at the rear (KC-29) a new reduced multi-spike tire to improve traction. This means steering remains positive even on rough surfaces with each wheel riding over bumps without affecting the stability of the car.
  6. Impressive! All those carbon parts take me back when Group C racing was king on the TV back when I was young in the 80’s. Nice build and so many carbon options! Like most here that built a 1/12 scale on road from Kyosho it’s nice to see these kits again. My first on road Kyosho was the Super Alta Porsche 956 in its Canon livery. It sat on the upper shelf in my room most of the time as it was super low and needed a large flat surface to unleash its speed. It’s such a drastic comparison to the Fantom, looking forward to seeing more options, great job!
  7. Interesting discovery along the way, the Graupner version of the Racing Baja Nr. 4948 vs Kyosho Nr. 3045 for all other sales region’s seemed they were provided with some upgrades within their kits to improve the steering and its durability. Both kits were released around the same time in late 4th quarter of 1983. The kits are the same, aside from the steering hardware and German language manual so, how did they get Kyosho to upgrade the steering kit for the Graupner sales region? After learning about the upgrades from other Racing Baja owners across the Atlantic I decided to track down the required components to upgrade to the Graupner Specification. When you compare the two different steering kits you can clearly see why Graupner wanted the upgrades, perhaps from a competition point of view it did not appear strong enough. Ball ends or ball cups and threaded tie rods have been the norm since the beginning with the Tamiya Rough Rider from the late 70’s so, why would Kyosho continue with the original circuit 20 series equipment for the steering kit which seems more fit for an RC airplane with its L-bends and Z-bends that connect with a Du-Bro ez-link type connection. Three components from the Graupner kit Nr. 4948 manual makeup the actual change at the front: 4948/1 Versteifungsplatte f. Servo-Saver (Item 23) 4948/2 Spurstangen-set (Item 16, 17, 18) 4948/X Servo-Saver, kompl. (Item 22) same as KC-3 from the Mint Las Vegas (Item 3, 4) The original servo saver which seems more fitted for a 1/10 scale car is carried on a steel bracket protruding from the left hand side of the chassis member. The original steering kit was more difficult for any type of toe-in adjustment. The Graupner version uses a chassis stiffener plate (Versteifungsplatte) positioned center with its much larger servo saver and fully adjustable tie rods and red ball ends. The excessive play from the worn out steering linkage is gone and the upgrade looks to be stronger and easily adjustable.
  8. Before we start exploring the true potential of the Racing Baja out on track let’s go over a few track side items that are critical for getting the car started to maximize performance. Fuel being the number one item as there are so many blends that are different from what we ran in the 80’s. If I remember correctly I ran Byrons fuel with 15-25% Nitro when I started out. I soon learned about performance fuels from K&B who I think at the time was the best you could get. Now let’s fast forward 35 years and today we see a big push from VP Racing Fuels for R/C Racing. I decided to try a quart of the 25% Nitro with 9% oil. RC fuels differ most with respect to their lubricant. Lubricant (oil) is essential to keep the engine’s moving parts working freely and to remove heat. VP PowerMaster premium nitro racing fuel is blended from 99.9% minimum pure nitromethane, anhydrous methanol and the highest lubricity, lowest-ash lubricants produced. Nitromethane contains nitrogen and oxygen which provide more fuel for the combustion process, more oxygen allows more fuel to be burned in the same space. More fuel plus more air typically equals more horsepower. Glow plugs are in fact a critical part of the whole performance picture. 3.5cc engines that run fuel containing a high percentage of nitro favor the cooler plugs, while those that run less prefer a hotter plug. I used the OS Glow Plug Nr.8 (Medium) and will be trying out the McCOY Racing MC-8 glow plug to see if there is any difference until I get a hold of some OPS “GOLD” RC300 glow plugs, which I heard were the go to plug of the 80’s. My Hobbico Deluxe Power Panel has seen better days as my field box was barely alive, I will need to rebuild a new one. Fuel jug on one side and the Sullivan Hi-Tork electric starter plugged in to the power panel on the opposite side, same with the glow plug. Pull out drawers for tools and miscellaneous items. That’s how we did it in those days as there were no starter boxes for the Circuit 20 Series due to the high position of the engine.
  9. After spending a good amount of time scanning the web for information (magazine reviews) regarding the Circuit 20 Series which consist of 12 kits from mid 70’s to early 80’s, I came up with almost nothing? I see a few articles on the original Fairlady 240Z and Land Jump 4D when these kits were first released so, what happen to all the other Circuit 20 buggies? Surely someone somewhere had to be racing these early 2 wheel drive buggies. Organizing such an event would be a huge challenge at the time. The local hobby shop would certainly have benefited from such an event. It seems France, UK, Sweden, Germany, Europe, Australia and USA all had major distributors for these kits as well as regional R/C magazines at the time. While not all magazines focused on R/C cars they did include them in R/C Airplane magazines as many hobby shops were now advertising within the pages. So, why no reviews for these 1/8 scale cars at the time to help promote the sales? One thing is for sure, 1/8 scale nitro On-Road was popular from the 70’s on thru the mid 80’s and beyond on almost every major continent. In certain regions where 1/8 scale Off-Road racing did exist under the EFRA (European Federation Radio Autos) it seems clear 4 wheel drive was the way to go. However they could have run both 4WD & 2WD within the same group in its early days until better rules were outlined or classifications established? This is where early evolving R/C racing information is unclear or better yet hard to find. Perhaps all manufactures at the time saw the sharp rise in 1/10 Scale Racing which required a smaller track and not to mention a lower operating cost for the average enthusiast. This would become the right path and 1/8 scale would become an even smaller segment in the world of R/C. That could be the reason why not many hop-up or option parts existed for these vintage nitro buggies. OPTION PARTS Kyosho CB-37 Front & Rear Stabilizer Kit This option is for the early Circuit Series like the Kit Nr. 2282 Fairlady or Kit Nr. 2283 Baja California as both have a notch cut out on the chassis plates for the front and rear stabilizer. These notches do not exist on later kits like the Rowdy & Racing Baja and use a different part number CB-121 for the rear stabilizer. The instruction sheet for the CB-37 is an actual ammonia blueprint and not a black and white photocopy.
  10. Moving on to the most critical part of the buggy, the engine. I still remember the cost of the Racing Baja and never understood at the time how an engine cost was more than half the price of the buggy or more. A top race engine like K&B, HB, OPS, Picco or OS Max was well over $100 USD. I guess because 1/8 scale nitro was the pinnacle of R/C racing and new for me, it was not going to be as inexpensive like my 1/10 scale electric setup. It was the ad listing that sold me: Capable of speeds over 50 mph and can climb over, jump across and splash through the toughest race course obstacles and still come back for more. Almost nothing from my small r/c car collection of electronic stuff could be used in my pursuit towards 1/8 nitro except for the transmitter, receiver and servos. It was at this point I decided to use my existing Enya .19 engine from my attempts in flying r/c airplanes. The engine was in great shape and bolted right up to the flywheel and clutch so, I used it to keep my cost down, eventually I purchased an OS Max .20 R/C engine in the coming months but it’s performance was more less the same. The third engine used was my first attempt at a more competitive engine, the UK based Irvine 20 CAR (ABC) engine which was the lowest priced performance engine in 1984 so, I decided to gave it a try. Compared to the Enya & OS Max I could feel the Racing Baja was staring to come alive! Throttle response was quick, the mid range and top speed was impressive! No way to tell just how fast the car was going up and down the neighborhood street. However there was a nice rich cloud of smoke trailing the buggy as it was screaming on by, not to mention the scent of nitro fuel in the air.
  11. We all know the importance of good electronics and how they have changed over the years. In the 80’s it was somewhat of an economical and reliable point of purchase. Following the trend it was either Futaba or Sanwa (Airtronics). Already having an FP-4L at the time from a crashed airplane I chose to use those electronics in the Racing Baja, knowing it was an airplane frequency vs a surface radio. As things progressed and I found true enjoyment with the 1/8 scale nitro I eventually upgraded to the state of the art transmitter in early 1984, the FP-T3PG. I made the choice in preparation for competitive RC Racing, more like a sport rather than a hobby. Itching to race the car somewhere at the nearest RC track. Upgrading from a 4 channel stick radio to a purpose built race quality device with all the various adjustments needed including my favorite the Warm-up switch. Throttle Warm-up is a device which automatically cycles the throttle servo between SLOW - MEDIUM SLOW - (HIGH). The red led lamp flashes to indicate that warm-up is being performed. Futaba FP-4L with FP-S28 servo (3.5kg-cm) 48 oz-in (.24 sec /60 deg) weight: (53g) 1.87 oz Futaba FP-T3PG with FP-S132H servo (1.8kg-cm) 25 oz-in (.13 sec/60 deg) weight: 32g 1.13 oz
  12. I have the Kyosho OT236R rear shocks are a good substitute over the CB-88/89 which are a hard find. They have piston choices for various shock oil weights/spring combinations. Careful not to over tighten the newer ones as the gasket is very thin and somewhat of a challenge to get them over the threads. The difference is length is 10mm shorter vs the original ones. As for leaking, one could use a small piece of Teflon tape or blue thread locker.
  13. Kyosho shocks that have lost there tolerance.
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