New addition to my "Kyosho family", a Turbo Optima, getting it ready to run again. - RC Groups
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Feb 16, 2014, 01:46 PM
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New addition to my "Kyosho family", a Turbo Optima, getting it ready to run again.

So, while working on some Optima Mids lately, in various varieties, I kept wondering how it would be to drive the car that started it all, the first generation Optima. I remember looking over Kyosho catalogs back in the days I was about 12 or so, and staring at the Optima and Turbo Optima pages. So whenever I was on eBay and other vendor sites lately, looking for Mid parts, I would also look at the classic Optimas on sale. Often too expensive, incomplete, seller not shipping to my country, and other pitfalls. Until I found an apparently well cared for one, not overly cheap, but value for money.

But enough talking, let's see how it looked when I go it.

Complete package:

Just the car, with body:

And without body:

I am no expert when it comes to this car, as it's my first classic Optima I've ever laid my hands on, but as far as I can see, the first impression is pretty good. The body shell has a few cracks, and some small chips of paint missing, but overall looks still very good for it's age, and will certainly be usable for running. And since the metallic blue tone works well with the decals and white wheels, it probably will even look good on the shelf. On one picture of the chassis, showing the steering assy, a plate near the bell cranks is only secured on one side, that can't be good, but the car feels solid, and the frame, despite being slender with those long gurders, is actually very stiff.

When pushing the car over the ground, some grinding noises could be heard, that will be te first to look into. Depending on what I encounter, I will decide whether to do a complete teardown, or just fix the issues I encounter, considering how well the car seems to be put together.

Update 16 feb 1014:

I mentioned the car feeling somewhat "gritty" when pushing it around. First I checked the external gears.

These could use some cleaning, but the gears' teeth look ok.except for a little piece of rock, that had jammed between 2 teeth. That was one cause for the drive train "hiccups" out of the way

The pinion was a bit too worn for my liking, and I will need to source a replacement, preferably a little tougher material than stock.

With the pinion off, and the flint of stone removed from the gears, the transmission felt much better, but would still "click" after a few revolutions of the wheels. Which led me to the 3rd problem, the chain:

Notice how, just above the oval shaped hole in the upper deck, a chain link is more v-shaped. This causes trouble as the chain rolls over one of the sprockets. I needed to fix that or get a new chain, to run the car.

Update 17 feb 1014:

So, I started work on the chain. First I considered removing the bent chain link, but after some more testing, I noticed more chain links were a little bent, and several smaller hiccups could be felt as the wheels where rotated. I couldn't take all ill-shaped links out, or I would end up with a too short chain. So I took out some pliers, and started the attempt to re-shape those links. At one time I almost got it right, but during a rolling test there was still a single small "hiccup". Studying the chain again, link for link, I found the culprit, bent it a little further open, and tested again. Now it was totally smooth. To indicate how light-going it now runs, if all wheels are off the ground, and you take one wheel, to rotate it, the opposite wheel will stay still, and the 2 other wheels will rotate along with the one you rotate. So the drag on the entire chain drive and gears is lower than on the gear diffs, eevn though the diffs are quite smooth. I think that's enough to ensure smooth operation.

Next step, further cleaning up of the external gears, rebuilding the shocks, and have a look at the servo saver and bell cranks.

Update 18 feb 2014:

Time for one of my least favorite tasks, cleaning up gears. I assume Tamiya Molydenium Grease was used, as the gears were covered with a silverish sticky paste. Or the metal that was grinded off the pinion during it's life, mixed with silicone grease, were the ingredients of the stuff that was stuck to gears:

For cleaning behind the "slipper gear" I put a piece of tissue between gear and motor mount plate, and rotated the gear:

A little later, the gears were looking much better again:

Next up was an unexpected task, I noticed the rear shock stay was not even close to being flat:

With a pair of pliers, patience, and some luck, I was able to get it about flat again:

After that, I removed the rear A-arm assemblies, one by one, to check the play on the axles and condition of the ball bearings. I didn't find any issues there, and after cleaning the dirt of the A-arms and dogbones, these were mounted again, with an extra washer on the inner pivot points, to reduce play. Next up was the front:

During this, I also took a good look at the front shock mount plate, and it was also a bit bent, although not as bad as the rear:

This took less effort to correct, and now it's looking like this:

Next up was the bell crank assy. I removed that completely, and discovered why it was not moving very smoothly. The metal posts, that the bell cranks were rotating on, were all gummed up, maybe with dried out grease or so. After some cleaning, light sanding of the longest metal post, and adding some 4 and 5 mm inner diameter shims to reduce play and friction, the steering assy was moving smoothly, and with minimal play:

The gear cover that came with this car was missing part of it's self adhesive foam/rubber seal. But I had a spare lying around, that came with a bunch of parts. It needed some cleaning, but made a perfect fit, so the gears are now well protected once again:

Next task, rebuilding the shocks. Like with most cleaning jobs, I used an old toothbrush, it's very versatile for cleaning almost everything, like spring coils:

Often missing or damaged on these old "golden" shocks, the shock bladders. But on all four these were still in nice shape:

The spring adjuster collars were also good, except for one, which was broken.

I have a few spares, so that didn't matter much. The flash from the camera, activated on purpose for this shot, shows the shiny inner surface of the shocks, revealing these had little use, or were well maintained. As you can also see, the oil that came from the shocks might be in for replacement, judging by the garish color.

It also felt almost like water, so very little dampening. The shocks were filled with Tamiya 400 oil I had a bottle off. Reminds me I need to get some extra shock oil in my "toolbox", I have plenty of the lower viscosity but almost nothing a little thicker. Shocks were fitted to the car again, and wheel angles were adjusted where needed, so the foam tires sit as flat on the ground as possible.

Update 4 march 2014

Time to mount the RC stuff. After some thinking, I decided wanted to keep the top deck of the chassis as clean as possible, and to achieve that, the ESC had to be mounted very low:

Is secured with strong double face tape, and on the front there is a small patch of the same stuff, holding it against the chassis brace.

Next was mounting the steering servo. First the mounting plate had to be cleaned off old glue remains:

Then I put on the double face tape, stuck the servo to it, only to find that the mount with servo attached can't be slid back into place without removing the radio plate, and the chain covers... So I removed the servo and the tape, applied some new, screwed the mounting plate back into place, and only then stuck the servo on the double face tape. The next pic shows part of the servo, and the routing of the servo wire, held to the underside of the radio plate with a little tape as well, so it stays clear of the battery, when it get's changed:

After fitting the receiver, the ESC switch and cleaning up the wiring, it looked like this:

Continued in the next posting, as this one has hit the max picture limit...
Last edited by SoloProFan; Mar 13, 2014 at 06:06 PM.
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Feb 16, 2014, 01:46 PM
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(reserved for updates)

After fitting the RC stuff, it was still missing the rear stabilizer. This takes some attention, as you need to remove the gear cover, and the middle gear to gain access to the screw that secures the right stabilizer holder. But now it really looks ready for action:

Update 9 march 2014:

Finished cutting the classic Optima repro body. It's a little too short, as often with TBG stuff, but I managed to get it on with acceptable fit:

And one shot with flash, looking a bit more like an "X-ray" shot:

Update 13 march 2014:

Some pics showing the masking and painting of the classic Optima repro shell. This is my first ever multi-tone body (I did once paint the rollcage on my Marui Ninja, but that was added later on the outside, so no masking was involved) and it's pretty complex, also because the body is pretty narrow compared to most modern bodies.

I did some tests with the red color, and backing. White does make the color more solid, but also lighter, and a bit too fresh/light for my liking. I tried black as well, but that almost "eats" through the red, and makes it like messy. Good thing I tested first on a piece of scrap lexan. So current plan, no backing, I just added another layer of red to make it more solid. And then apply the white later on.

Update 14 march 2014:

I added another coat of red yesterday, and after it dried well enough, I started on the white. I needs one or 2 coats on some sections, as this body has more hook and nooks than average, and the blue overspray cover is also still on, altering the colors a little:

Update 15 march 2014:

Painting is done. I had to re-touch a few small areas, where either the paint had been creeping a little under the masking tape, and at some places there was a small gap between the red and the white, so you could see through it. But I think it turned out pretty well.

Looking forward to adding decals to this, and bring it to life.

Update 16 march 2014:

Decal adding time! First I did a dry fit, to see what would look best:

After that it was time to put the decals on for keeps. I think the result is pretty nice:

And this is how it looks from the inside:

Update 17 march 2014:

Time to put the painted body on the car. Pictures speak for themselves, I think.

Last edited by SoloProFan; Mar 17, 2014 at 04:54 AM.
Feb 16, 2014, 01:46 PM
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Update 5 april 2014:

I decided to keep the foam tyres for display only, as the risk of bit chipping off seemed too big. Plus these are ideal tyres to put the car on display on a shelf with, as at the moment these are so hard and dry, that no flat spots are formed if the car is left on it's wheels instead of on a car stand. I still had a couple of Optima Mid rims, which are also 2.0 inch, and got a few more Schumacher Full Spike 1.9/2.0 inch tyres with inserts. After attaching the tyres (I didn't glue these, as the fit was pretty tight, and the rubber quite sticky, so the tyres can't really slip on the rims unless a very strong motor is fitted) and balancing, the car was ready for a first test drive.:

The car handled pretty well, and was more quiet than I expected from a metal chain drive. Tracking was straight, I just needed a little trim on the steering, which I did mechanically, by lengthening the rod between steering knuckle and bell crank on one side, and shortening it the same amount on the other side.

Top speed measured with GPS was a little over 35 km/h, 35.4 km/h to be precise. Not sure if this is the max performance of the current vintage motor, but speed felt ok for a vintage runner. If I want more power, I woild probably need to replace the chain with a belt anyway, as the chain tends to stretch if a very "hot" motor is fitted.

Here are some vids (HD versions will follow, when I uploaded these, my "HD quota" on Vimeo for that week was already spent) showing the car's handling. During one vid I had to make an emergency evasive move, to avoid a recessed part of the road, where an access hatch to the sewer is located, and the car handled that without any unpredictable reactions.

First testrun with a restored Kyosho Turbo Optima vintage 4WD RC Buggy (part 1) (0 min 44 sec)

First testrun with a restored Kyosho Turbo Optima vintage 4WD RC Buggy (part 2) (0 min 37 sec)

Update 24 april 2014

As some mentioned a classic Optima is not complete without the front bumper, and it would also eliminate the risk of the bumper getting misplaced and gone missing, I put it on today, and took some more pics. Also the first time I shot pics with the repro body on, and the spike tires. Enjoy!

Last edited by SoloProFan; Apr 25, 2014 at 02:31 PM.
Feb 16, 2014, 06:44 PM
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Looks real clean. Looks like the turbo optima is the same as the optima, so I can look for one of those as well. It just has the option house shocks and sway bars. I had RC10 shocks on mine they worked great. The stock red shocks were no good for dirt use, they got dirt inside and would sound crunchy. The rattling is a loose chain or partially stripped teeth on the diff sprockets. You will see that some holes on the frame are slotted toward the front so you can adjust tension. This needed to be done every few runs. Don't run it how it is, it will get worse and damage the diff sprockets beyond use. They will work fine with minor damage with proper tension (light tension, very light). Usually, the chain will lock up inside, requiring partial dis-assembly of the car to get it loose. You might also need to remove a link to get it right. Get a spare chain when you can find one. Man, I am envious! And keep those wheels with the slicks! You will want to run it on the street a lot to keep it nice. Those foam slicks aren't made for buggies anymore, I had a set for the smaller standard optima wheels. It actually handles very good on the street compared to other buggies. It is a stiff chassis, and was much better and high tech than anything in it's time. Looks like the regular optima body will fit it just fine.

Did you notice that it has aluminum hubs on the front? The original did not have that. Either it's another turbo part or an option. What a sec, now that I'm thinking... the original did have aluminum there.
Last edited by shahram72; Feb 16, 2014 at 07:16 PM.
Feb 17, 2014, 12:15 AM
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Thanks for the praise and helpful suggestions. It is indeed as you mention, the Turbo version has a few upgrades here and there, most obvious the shocks. It also has a torque limiter which I am not sure is also present in the regular Optima. But apart from that, the classic Optima body should fit, I also got confirmed from Team Bluegroove, who should know, as they make repro bodies for both cars.

The hiccups in the drive train were not caused by a loose chain or damaged diff sprockets, but there were 2 other causes making it grind and feel a bit skippy. Good call on the advice not to run the car "as is", as the risk on more damage is way too big.

I already intended to keep the wheels, I like these Option House ones. It looks a bit like a stock car with those foams. But will these still be durable after so many years?

Update added...
Last edited by SoloProFan; Feb 17, 2014 at 02:50 AM.
Feb 17, 2014, 12:40 PM
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Very very nice!! One of my favorite cars of all time right there. Subscribed and anxiously awaiting updates and the 1st drive.
Feb 17, 2014, 01:34 PM
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Nice find! My old school is limited to mostly Tamiya when I was young.

I will be watching!
Feb 17, 2014, 01:51 PM
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Thanks! I do intend to also get a classic Optima body for it, but the metallic blue on the Turbo Optima body that came with this car, also works very well.
Feb 17, 2014, 03:07 PM
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Originally Posted by SoloProFan
Thanks! I do intend to also get a classic Optima body for it, but the metallic blue on the Turbo Optima body that came with this car, also works very well.
Yep it does, and when I do an original Optima I will want both bodies for it as well. I'll also want a set of foam tires for it, but unless I do them myself it will probably take years to score a set.
Feb 17, 2014, 03:35 PM
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Never knew those foam tyres were so hard to come by. I remember in the beginning, when I first set eyes of the auction, feeling a little disappointed there were no pin tyres on the rims. But I learned to understand I should treasure these foam tires.
Feb 18, 2014, 10:23 AM
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Update added, cleaned the gears and reshaped the rear shock mount plate.
Feb 18, 2014, 10:41 AM
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Gears and shock mount are looking much better. Good to hear you got the chain all straightened out too.
Feb 18, 2014, 02:12 PM
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Added some more pics and story. I am currently working on the shocks, should I shoot some pics of those? I often leave these pics out, since I think you've all seen these shocks inside and out often. Or is that a wrong assumption?
Feb 18, 2014, 02:45 PM
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I'm sure there are those that might find the pics helpful in the future. I often leave those pics out of my builds as well but should probably start posting them.

You're gonna have that thing up and running in no time
Feb 18, 2014, 03:02 PM
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Originally Posted by fastmax
I'm sure there are those that might find the pics helpful in the future. I often leave those pics out of my builds as well but should probably start posting them.

You're gonna have that thing up and running in no time

Ok, I've got 3 of the 4 shocks done, but will shoot some pics when I work on the 4th.

Things are moving pretty fast indeed, the quality of the base material in this case is pretty high, and so far almost zero parts are missing or damaged beyond repair. But I do need a new pinion, and that will not be as easy to get, as these cars use module 0.8 gears.

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