1980’s Buggies - A Scorpion some RC10s and a quick Javelin detour

[njmlondon]

Buggies captured my heart from the moment I first saw a Tamiya Super Champ on the promotional video at my LHS back in the very early 80’s.

Then there were the Tamiya Handbooks with pictures like this…

The discovery of Blockhead Motors and the 380 motor revival have revived my love of them and I now have a Kyosho Scorpion, Tomahawk, Team Associated / Fan RC RC10, Tamiya BBX, Wild One and Fighting Buggy all lined up.

I thought I would try to do a build log, for those of you interested in some of the tweaks I will make to these great models.

Nowadays I have a very clear idea on what I want to achieve with each build and never build box-art or stock.

All my cars are built as runners but do not get run very often, so they need to be robust, not need much tuning and just be able to go on demand.

Over the years I have developed a standard set of upgrades I always install from day one… universal shafts (lost dog bones ruin a rare driving opportunity), turnbuckles (for strength and easy alterations), steel pinions and I always try to use a gear-diff rather than ball-diff if possible.

So enough pre-amble, let’s look at the first project. The Kyosho Scorpion, with its rail chassis and classic shape, was always on my list, but as you will see through this thread, I almost always mix n' match and build "bits" cars to get exactly the look and performance I want.

I have spent several wonderful hours in the garden today doing the first few stages and will sort out my photos overnight and get this thread going. I hope you enjoy reading it, please feel free to ask questions and / or critique my decisions and techniques!

[Juggular]

Welcome back?  Your writing gave me an impression that you just discovered the hobby. But you were one of the few people who joined when Tamiya club started in 2002.  When I joined in 2004, you were already a well established member. Which means I learned a lot from you.  I find myself in a cycle too. I go full throttle for a couple of years, lurk for a few years, and come back again.  At any rate, welcome back. 

I used to lose the hexa-bone on my Blackfoot all the time.  I was running it on a very rough surface.  The back alley's broken cement was really bad.  Much later,  I bent the dog bone on Mad Bison nitro.  But since then I use an o-ring or a piece of sponge, so the dog bones would not go too far in either direction.  To pop out, it has to go deep into one side, so it would come out from the other side.  I find that they are fine if they stay in the middle (without binding, so sometimes I cut an o-ring in half like a bagel to fit just right).

I also find that the Sport Tuned is the upper level for me.  I have a couple of brushless, but going faster means less control for me. If my driving skills were better, maybe I could enjoy both speed and control without rolling the car on its side.   finally managed to mix the channels, so higher speed would give me less steering. So that will help.  But I like tinkering more than driving anyway. And the $15 Sport Tuned is a good match for most Tamiya kits.  Except for M-chassis.  The stock silver can is fast enough for parking lots.  

Some buggies came with faster motors, at least in the US (which is a good call, since streets are much wider here). MF-01X and DT-04 came with Torque Tuned which is about 15% faster than the silver can (Sport Tuned is 30% faster).  As long as they are not the silver can, I use what Tamiya gives me.  

Full bearings alone would give me 15% speed boost anyway, so another 15% from a Torque Tuned is fine by me.  My Bigwig came with GT tuned, so I use that too.  

But, I'm curious about the 380 motor.  Why 380?  When I raced on-road, I did use 380 when other kids had upgraded to 540.  I tried it, but I downgraded to 380 again because 540 was like a wild horse that I was bucked out of. I placed 3rd, only because 380 was much easier to control.  

 

[njmlondon]

14 hours ago, Juggular said:

Welcome back?  Your writing gave me an impression that you just discovered the hobby. But you were one of the few people who joined when Tamiya club started in 2002.  When I joined in 2004, you were already a well established member. Which means I learned a lot from you.  I find myself in a cycle too. I go full throttle for a couple of years, lurk for a few years, and come back again.  At any rate, welcome back.  

But, I'm curious about the 380 motor.  Why 380?  When I raced on-road, I did use 380 when other kids had upgraded to 540.  I tried it, but I downgraded to 380 again because 540 was like a wild horse that I was bucked out of. I placed 3rd, only because 380 was much easier to control.  

Nice to see you Mr J. Where did those 20+ years go!? Not sure you learned much from me! I was busy learning from the likes of Shodog (RIP!) and the other gurus as I embarked on building my 959 and restoring an OG Hilux. 

The 380 scene seems to have exploded in Japan and then caught on here in the UK. It was a thread about Club 380 that got me thinking about enjoying a slower pace of driving and then I started watching some videos about Pine Beach Raceway where they promote "Healthy Racing" and I just loved it.

The buggies all look so cool scooting around at a vintage pace. Having done some research I found out that the 380's are not really much slower, but they do have less torque, which leads to more realistic and relaxed acceleration but still with a similar top speed. There are some real life benefits to a 380 too. It is half the weight of a 540 and uses less power so run times are increased a lot. The Kyosho Scorpion and RC10 are both incredibly light so 380 is more than enough. My Fighting Buggy and Scorcher will weigh a tonne though so for them I think you need the grunt of a 540.

[njmlondon]

Right so let's get stuck into this Scorpion. For those of you who have not yet given the Kyosho Legendary series a go, I would suggest you do. The whole experience is an absolute joy. The parts are gorgeous, the instructions flawless and the end result a real gem. As a kid I only saw Tamiya and although I still love my SRBs, it is incredible to think that in 1982 when the Super Champ was released, Kyosho was releasing the Scorpion which is frankly, considerably superior in almost every way.

I have got myself a Turbo Scorpion manual and will be mix and matching as I go through. The Turbo front and rear shock towers are longer to accommodate bigger shocks and I am hoping I can get the gold shocks for the front of the Optima to fit easily. 

Stages 1 through 4 literally fall together. I had to remember that not only was I swapping in the taller front shock towers, but I also needed to change the 15mm screw for a longer 18mm one, because not only are the Optima shocks longer, but also fatter.

The next bit is actually quite tricky. You have to squeeze the front arm stay into 2 retaining blocks but it needs to be very precise to get the spacing correct and the angle right. It requires a lot of torque on the screws to pull the blocks down to the ladder frame so make sure you have good quality hex drivers or it would be very easy to strip a screw head.

The RO MANS 380S from Pine Beach is a little gem and the alloy mount perfectly engineered to fit the Scorpion. The gearbox comes pre-built along with the diff, but I took it all apart, applied liberal amounts of grease and rebuilt it, mainly just because I enjoy building gearboxes. I did change the pinion to allow for higher top speed at the expense of acceleration, which is the driving characteristic I am going for. It was a real battle to get the retaining ring off the pinion and back on. Much swearing occurred but eventually it all came together. 

The final stage for today was bolting the motor onto the ladder... starting to look like a buggy. The Scorpion has a metal cover for the gearbox and the wing mounts on a wire that attaches to the rear cage, but I am going to be using an alloy one from Pargu so I installed the Turbo wing stay.

What a very enjoyable few hours that was. My wife is off seeing friends tomorrow, my kids are out and the dog and I have the place to ourselves, so after a bacon sandwich for me and some stick chasing for him, I'll be building some gorgeous shocks and getting the suspension set up. I do love bank holiday weekends!

[Juggular]

Given my own experience with 380, I do love the idea of 380 racing.  It sounds like racing to enjoy, rather than to get stressed out about winning.  

Years ago, I've asked "must have Kyoso" but haven't pulled the trigger.  Your thread is reviving the need for speed... er, less speed. 

 

[njmlondon]

The forged aluminium suspension arms are so light compared to the pot metal of an SRB and quite beautiful to handle.

The rears are actually quite fiddly to get right. You have a bar that goes through two eyelets in little sprockets that screw into the main chassis. There are 2 angles at play, both horizontal (the arms are at an angle to the chassis) and vertically (the arm is higher on the outside).

Because I was using the universal swing shafts, I did not have to worry about getting the dog-bone in at the same time, but you really have to coax the whole thing together. It is almost impossible to get the eyelets perfectly true with the bar, as you tighten the screws they want to rotate the sprockets and this causes it all to bind. You need to tighten up a tiny bit at a time and then back out, free up the binding then go again several times to get it utterly free. 

The front sub assemblies are more complex to assemble, paying a lot of attention to the instructions to make sure you get the ball ends the correct distance away from the arm with one projecting 7.5mm and the other 8.5mm. However once they are done they just slide straight on. 

The camber control arms and the steering links are then attached. I did not swap these out for turnbuckles but may come back to that in the future. I think there is a lot you can do with the front suspension of this buggy and I am really interested to experimenting with the geometry and shock /spring choices along with the front tires. As a rear motored 2WD the front is bound to be light, even with only a 380 out back, and it would be nice to dial out understeer. 

So that's pretty much the chassis done.

Shocks are up next and I really need to think things through.

I have a short wheel-based Scorpion, with a 380 motor out back so am c100g lighter than the standard model which will move the centre of gravity quite a long way forward compared to a stock build. 

I am using the Turbo Scorpion shock mounts, but using Optima Gold front shocks and all 3 sets of instructions (Scorpion, Turbo Scorpion and the Optima Shocks) call for different oils, pistons and springs so I think there will be some trial an error finding the right balance for this. The shocks are very pretty though!

[njmlondon]

A couple of new motors from Pine Beach arrived, the 380AH tuned by Atsuri Hara. I originally bought one for my next project, a FAN RC RC10 hybrid, but I liked the purple so much I could not help myself but swap out the Sukoyaka tuned 380. I have no idea whatsoever what difference, if any, there is between the motors and it was simply a cosmetic change. I will plop the red 380 into my Tomahawk project when I get around to it.

As mentioned earlier, I decided to upgrade the standard short shocks that come with the Scorpion for ones that are both longer and fatter, and am using the front shocks designed for the Optima / Javelin that have threaded bodies and not the screw-fix collars, making adjustments easier. You have to use the shock mounts that are used with the Turbo Scorpion and remember to use longer screws and spacers for the larger diameter. 

These Kyosho shocks are bottom-loaded using a rather nice tool set that Kyosho provide for the job and they were a pleasure to build. I swapped in some x-rings for the standard red o-rings which apparently should aid in sealing the oil in the shock, covered the rings liberally with green slime and used my new shock pliers (how have I lived without these for so long!?) and got the buggy on her wheels. 

I then strapped the radio box and battery on to get the weight right and did a series of tests, using my slow-motion setting on my phone. I dropped the car from 1 foot and recorded the way in which the suspension behaved. It took me a while and a bit of experimentation, but I got there in the end and think I have a lovely, balanced set up as a base point.

For those of you considering a Scorpion or equivalent, I swapped out the front tires that come with the kit for a set of mediums. The hards are really hard, more like a plastic than rubber. I ended up using 350 weight oil in all the shocks and built them as per the Turbo Scorpion manual with slightly larger piston holes in the front.

For the rears I used the stiffest springs, the gold ones and for the fronts I ended up using the pink Medium Softs. Obviously I may need to tweak it when I see it running, but am happy with this as a start point. 

Finally an aftermarket alloy bumper by Xtra Speed and a lovely alloy wing from Pargu were bolted on and she is now ready for electrics and the body. 

[officepizzaparty]

looks so good, you're making me want to do a 2wd kyosho!

[toyolien]

Fantastic thread, and write up. I also was first drawn to the 80's looking buggies as a kid. Will be following a long with great interest.

[Andreas W]

Nice writeup and build. Following this with interest. 

 

PS: Fill up the top of the front crossmember with stickon wheelweights. That does good for the steering. Idid that when I had the Yeah Racing Hackmoto 23t in it and left them in. The steering response with the 380 is superb. 

[Grumpy pants]

Following and looking forward to more 😊

[njmlondon]

14 hours ago, toyolien said:

I also was first drawn to the 80's looking buggies as a kid. Will be following a long with great interest.

Thanks. It was one of your builds, a 380 Scorpion that put this build to the top of my queue. Going a similar route to yours but less HD parts and a bit more cosmetic changes.

6 hours ago, Andreas W said:

PS: Fill up the top of the front crossmember with stickon wheelweights. That does good for the steering. Idid that when I had the Yeah Racing Hackmoto 23t in it and left them in. The steering response with the 380 is superb. 

Thanks for the tip, I follow your adventures with your Tomahawk in the Postal Racing and will take your advice!

[njmlondon]

Last night the radio tray received its servo. Probably gone overboard but used a lovely Savox low profile servo that I had lying around. The battery box is huge and accepts my 5000mah Spektrum Smart battery with ease so run times, when combined with a 380, should be incredible. 

I have combined the standard Scorpion body with the roll bar and lights set that comes with the Turbo Scorpion and am very happy now with the overall look.

I am going to get the electrics all done this week and run a pack through on the bench to ensure it is all smooth and that I understand the settings options on my new Hobbywing 1080.

I have to wait for the MCI decals to arrive before painting the body. I really want to use an off-white old school racing white but want to see how the colours work in the flesh before deciding. In the meantime I will start to paint the cockpit which will be painted on the outside using acrylics and finish the helmet. 

And I will probably not be able to resist starting some work on the Fan RC RC10. Whilst I enjoy electric work and painting, I am never happier than with screwdriver and wrench in hand working on gearboxes and suspension!

[Superluminal]

What front springs are you using? I built a bits and bobs "Turbo" Tomahawk with the same gold shocks a couple of years ago but found the springs were a bit too hard for the lightweight front end.

[njmlondon]

5 hours ago, Superluminal said:

What front springs are you using? I built a bits and bobs "Turbo" Tomahawk with the same gold shocks a couple of years ago but found the springs were a bit too hard for the lightweight front end.

The Kyosho Optima (front) shocks are the same length and diameter as the shocks used on the Turbo Scorpion and also the front springs of the Ultima. It is not obvious and it took me reading through all of the manuals to work it out, but there is option pack (OTW123) which has Silver/Soft, Black/Medium and Gold/Hard options. They also do a fine tuning range of Medium Soft and Medium Hard (UTW009) which are sold as Ultima Springs but actually compatible with the Turbo Scorpion and Optima.

I used the pink marked Medium Soft and am really happy.

[Superluminal]

1 hour ago, njmlondon said:

They also do a fine tuning range of Medium Soft and Medium Hard (UTW009) which are sold as Ultima Springs but actually compatible with the Turbo Scorpion and Optima.

Gah - of course, the Ultima springs!! I had already bought the Optima set and it was these that felt too stiff, which in hindsight should have been logical given the additional front end weight of a 4wd.

Cheersl!

[njmlondon]

It’s been a while but the Scorpion is finally back from the paint-shop. I wanted a cream white for that late 70's / early 80' vibe, but obviously nobody makes a PS paint in that colour. I love TS-7 Racing White so did some research. All I knew was that TS paint is not flexible and therefore not recommended, but it turns out that the main problem is actually that TS paint does not adhere to polycarbonate and will flake.

This is not a touring car body and won’t be subjected to the same forces, so flexibility is less of an issue (I hope!) so I went with PS flat clear as my "primer" which leaves a lovely surface for the TS-7 to adhere to, backed by PS White then PS Silver, all delivered in ultra fine layers over a period of days and I am hoping this will hold up. 

Next up is to remove the radio box and paint a bit of it for my design and get the tire lettering done. I also need to mask off the whole of the outside of the body apart from the cockpit, hit it with PS clear and start detailing the driver with some acrylics. 

My next project has also just arrived so I think I will be mixing up my time, some evenings on finishing this Scorpion and some with spanner in hand, on something completely new to me. You may be able to guess what it is.

[JimBear]

44 minutes ago, njmlondon said:

You may be able to guess what it is.

It's a large indoor fan on wheels?

[Andreas W]

That turned out gorgeous. Now you can look forward to healthy running. 

 

I am going that paint route with the Fabia body for the XV-02, since I saw no way around the TS green candy.

[njmlondon]

18 hours ago, Andreas W said:

That turned out gorgeous. Now you can look forward to healthy running. 

The more I look at it the more I love the simplicity of the colour combination. I spent many hours on the decal creator at MCI coming up with several early 80's style vibes, but am now wondering if I should keep it ultra simple. I will crack on with the driver and cockpit and see how I feel when the decals finally arrive. I definitely need something healthy in my life right now!

[njmlondon]

So, as you may have guessed, the yellow box in the background is indeed an RC10 from FanRC. But no ordinary FanRC10, if only life were that simple. This is a proper "bitsa". I did not start looking at RC10’s until I recently took the red pill and cheated on Mr T with Kyosho. Once a brand-tart, always a brand-tart!

The RC10 had many reasons for me not to be interested. I had no nostalgia for it, did not see them in my youth, was put off by the prices, the imperial hardware, the reports of poor tolerances in comparison with the Japanese brands and the reports of poor parts availability. Then I posted a question in the re-re section and started to change my mind. Maybe once would not hurt. Nobody need know. I could always sell it and pretend it never happened.

So once I crossed the Rubicon, the decision was which one to get? I fired up my OCD and started reading up, watching too many videos and scrolling through Pinterest and Instagram to get inspiration. As usual, I wanted something that did not actually come as a kit. Typical. Visually I wanted a gold pan chassis which is the signature feature, and probably the Mirage body combined with nice splodgy tires. I also wanted my usual mechanical upgrades, namely turnbuckles and a decent diff. The Gold Team Car comes close but the wheels and body are not what I wanted, which is when I stumbled across FanRC. I had never heard of them but found Lee at LandL is the UK importer and we got talking. 

For those of you who are RC10 newbies like me, FanRc was originally set up to supply reproduction parts for the non-supported vintage RC10 scene, and this mushroomed to a point that they were offering a complete car, that the RC10 gurus online claim was at least as good as, if not better, than the original.

The one that caught my eye was the Graphite Worlds Kit but I wanted an aluminium chassis, and because I wanted chunky tires, I knew I needed 1/4" axles and Lee was able to accommodate and swap a few things around. I had also learned that Team Associated were continually evolving the kits mid production and that one box may have some of the newer black nylon parts in, leading to what became known as the "zebra" cars, which rather appealed, so a few parts were exchanged for black ones and some carbon was swapped in. 

I started the build last night and have just finished up for tonight, so I will sort the photos out in the morning and we can see what all the fuss was about back in the early 80's. But as a teaser, here's what we start with... notice, no body (I am going to go for a JConcept one), no wheels (I have my eyes on some rather cool aftermarket ones) and most importantly of all, no instructions (yikes!). But lots of lovely bags of gold and ivory perfection with a sprinkling of carbon. Yummy!

[njmlondon]

OK, what have I done!? 

FanRC do not provide any instructions. I mean any! I downloaded the Team Associated Classic 40th manual, Gold Team Car, the just Released Kinwald Worlds and the Halsey just in case. They are pretty good, but inconsistent. Sometimes there are part numbers, sometimes names, things that look identical are not, and everything is in inches. 

A side investment in some quality Imperial Tools was essential and we start simply, joining the main chassis with the nose which will hold the front suspension. 3 screws hold the whole thing together which feels a bit weak to me, but that’s what they designed so let’s see. So I tighten them up, but it all feels sloppy, the screws are not sitting flush in the recesses at the bottom. Dismantle and examine and then realise that there is a tiny lip, maybe 0.1mm of anodised overflow around the holes, so out with an ultra-fine metal file  and it all goes together perfectly and there is no play at all. 1st rule of RC10 club. Inspect everything, it's not Tamiya.

Once in though, the chassis screws double as the holders for the bell crank system and once fitted as per instructions (holding the car upside down above your head) it is ultra smooth. 

Next up is the front shock towers attached to the nylon arm-hangars, which is again, simple and elegant. The first thing you notice is how unbelievably tight everything is, you really need to have a decent hex driver and put some torque through it. The nylon is a lovely material, with a surprising heft and density and you can feel the bite. Mmmm... gold metal, ivory nylon and carbon. Tasty.

You will see from the photo above though that I got my 3/16ths and my 11/64ths mixed up and I used the wrong screw attaching the tower to the bulkhead. This is when we also learn something about the RC10. It is designed to use the absolute minimum amount of screws and bolts and every single one of them is accessible even when everything else is bolted on. Clever. you can see why racers loved them. 

We also have our first mix n match, with screws in inches and the balls in mm. One is 3mm and one is 2.93mm so obviously I used the wrong nuts and found myself cross-threading them. I know a M2.6 x 10mm from a M3 x 12mm blindfolded, but I found myself consistently having to translate 3/16, 5/64, 7/32 into mm. In the end I did myself a cheat sheet with every measurement converted to millimetres. There are 3 different ways of splitting an inch... screws are 4-40 which refers to the diameter and is 2.84mm x 3/16th long which is 4.76mm and sometimes they are referred to as 0.125 of an inch. Hard work!

The rear bulkhead starts to teach you how these cars rely on tension to create their renowned strength. I make the mistake of fixing the bulkhead tightly to the bottom of the chassis then realise I cannot get the side retaining screws through, so have to back the bottom ones out, jiggle it a bit then gently tighten them all up a turn each at a time and by the end it is rock solid. The sooner you learn this about an RC10, the better. I think this may be why people say the tolerances are poor, that things do not line up. I am learning they are designed that way so the combined push /pull creates a solidity and complete lack of play that I have not experienced in a Tamiya or Kyosho. 

That's all you are getting for today. I have built the diff and got the front arms on but not sorted the photos and we have plenty of time as I take a break from building over the weekend to head down to the coast to see friends, and pick up a bargain new built Wild One Blockhead that I found on FB Marketplace about 1/2 hour drive from where I am staying.

I need a runner right now, but these buggies demand and deserve the time and effort to get them absolutely spot on so they won't be out and about for a while. I have built Wild Ones before so don't feel the burning need to build another, and I have a 380 motor on the bench, so that's going into it for some Postal Racing. 

[Grumpy pants]

There is sooo much to like about this thread! 

[njmlondon]

This RC10 just keeps on getting better and better. The early RC10s all came with something called a 6-gear gearbox which gets a lot of criticism. Apparently the original ones took a lot of time and effort to get them to run smoothly and by all accounts, the re-released one are not amazing either. I may have to get one to see for myself though.

Either way, Team Associated decided to upgrade their gearbox to a ball-diff and it was used in one of the World Championship cars (I forget which year). The car won everything and it only later became known that they had quietly dropped this massive upgrade into the chassis. It was nicknamed the "stealth" because of the way it was snuck into the car and that stuck. This car comes with the FanRC diff and as I am about to learn, it is not exactly the same as the re-re diff. It took me a while to find out but there are subtle differences between the original 1990's Worlds Stealth Diff and the Stealth Diff you find in today's Gold Team Car and Kinwald editions, so you have to go and find that older version.  It is really interesting to see how different Team Associated instructions were in those days. Tamiya instructions have stayed the same all the way through time in terms of detailing, layout and styling. 

Once built I give it all a good twist back and forward. The good news is that I can already work out that tightening or loosening the ball diff in the future will be very easy. The screw will be accessible simply by popping off one of the rear turnbuckles, removing the universal shaft to get to the screw hidden in one of the white plastic parts you can see and then re-assembling. Last time I had to tighten a ball diff on my M05 I am pretty sure I pulled almost the whole car apart!

I was not happy though with the feel of the diff. It was smooth and progressive but felt a bit crunchy. Some time spent online indicates that this is normal with a new RC10 diff and it would bed in after a few packs, but I pulled it apart anyway and decided to give the 2 diff rings a light sanding to get a mirror finish on them. You can see from below that it was worth it and when back together and a noticeable improvement. 

Time to attach the motorplate and get the whole thing tightened up. Once again, the completed sub-assembly is rock solid, no play at all, highly impressive.

By now I knew a bit more about the correct approach to the next stage. There are 4 holes in the bottom of the diff that receive screws from underneath the chassis, 2 holes in the top that are screwed through to attach to the bulkhead with a carbon brace and the motor plate has 2 holes in the rear that will join the main chassis. So I put the first 4 in from underneath but only screwed them about 1/3 of the way in. Then the same with the diff brace and then you can see how far out you are for the rear 2 holes. 

The screws you are going to end up using here are only 3/16" but I started with 1" long ones to get the 2 parts to bite, tightening up the 4 bottom screws, the 2 brace screws and these ones a turn at a time, one after another. At the last minute I swap the 1" screws for the correct 3/16th ones, now the motor plate and thee chassis are close enough together to fit straight in with the correct spacers, and it all comes together in a remarkably strong unit. Slipper clutch pops on easily, and we are done.

[Big Jon]

I’m enjoying your builds!

Are you aware of the RC10/Tamiya connection? The Stealth transmission is Associated’s take on the MIP three-gear aftermarket transmission. The MIP transmission is based on the SRB three-gear transmission, and the first production MIP transmissions were for SRB. The slipper came much later.

The six gears were not bad at all. Yes, they did require some extra care when assembling, but all race cars required care. The diff was easily accessible and they used readily available pan car spurs for a wide range of gearing options.