Kyosho Raider Restoration (part 3)

On to the final part of this Kyosho Raider restoration: finishing the body, wing and wheels.

In the past I have generally used curved lexan scissors to trim polycarbonate bodies.

Duratrax lexan scissors

These scissors are specially designed to aid in trimming excess lexan due to the curved shape of the blades.  They work quite well for general trimming and going around outside corners, but I've found them hard to use around tight inside corners, especially if the lexan is thick and won't bend out of the way easily.

Another method modelers use to trim lexan is a technique called scoring.  Using a sharp knife, a score line is made along the body either right on or just outside the molded trim line.  The depth of the cut does not have to be very deep to be effective although deeper cuts do help in cases where the lexan is fairly thick.  Once the body has been scored, strategic cuts can be made using lexan scissors or the knife blade to allow the excess lexan to be bent and or ripped along the score line.  The resulting edge is quite clean, similar to how glass is scored and broken to create a clean edge.

I used the scoring technique on this Kyosho Raider reproduction body and wing from Team Bluegroove due to the many curves and thickness of the lexan.  Using a brand new X-Acto #11 blade, I scored a trace line on the outside of the body, cutting through the protective blue plastic layer and into the body.  The key is to make a continuous score line so the plastic can be bent and ripped apart cleanly.  When separating the trimmings from the body it helps to go slowly in case the lexan doesn't want to follow the score line as it is ripped apart.  A body can be ruined very quickly if the lexan rips into the wrong location.  The knife can be used to help cut in places where it looks like the score isn't deep enough.

Once the excess parts were trimmed and the body was separated from the wing, I used sandpaper and a small set of flat files of various shapes to fine-tune and smooth the edges.  

Needle file set and 100 grit sandpaper

I also made sure to round all corners to varying degrees to remove the sharp edges using mostly rough sandpaper.  I haven't found a need to use finer sandpaper because the edge is smooth enough already.  Finally, I test-fit the body to the chassis and marked the placement of the holes for the body mounts, antenna, and wing.  Using a body reamer tool, I made holes in the marked locations, taking care to not make them too large.  On this body, the rear body mount hole is actually rectangular, so the X-Acto knife and flat files were used to shape the hole into the final size.

Kyosho body reamer

The trimmed body and wing before final washing, masking and painting:

Since this is a reproduction body, the dimensions are not always exactly the same as the original.  Most people would agree that while Team Bluegroove bodies are decent quality, they do not always match the fine detail and dimensions of the original.  In the case of this Raider body, I think the length is slightly shorter than the original Kyosho.  Due to this, I had to put the rear body mount hole further back than depicted in the Raider manual.  

The rear body mount hole is supposed to be on the rear part of the roof

Here is the body mounted on the chassis:

As you can see below, the rear body mount hole is right in the middle of the near vertical area where the rear roof drops and goes to the rear deck of the body between the shock tower posts.  This hole location seemed to be the best way to balance the position of the front of the body with the shocks and steering linkage with the rear shock mounts and rear body overhang.  The body slightly overhangs the rear gear case which looks great. Thankfully the top hole of the rear body mount is high enough so a body pin just clears the roof deck and keeps the body secured.

Rear body mount hole is rearward of the location depicted in the manual

The front body overhang is almost in line with the front of the suspension arms which I also think is aesthetically pleasing.

Front body mount hole is close to the default location

Given the center line locations of the front and rear body mount holes, the body isn't very stable side-to-side.  If the rear body hole was in the correct roof location as shown in the manual, I think the body would have been stabilized by resting the shock tower recesses molded into the body on top the rear shock tower.  I can still use the shock tower recesses to stabilize the body by using screws set to the proper depth in the top of the shock tower.

I used Tamiya PS-2 Red (86002) backed by PS-1 White (86001) for a box art look.  Perhaps I should have used silver or black as a backing color to darken the red some more.  The camera makes it look more neon than it actually is.

Applying the decals is fairly simple to do.  I use a small tub of water with a few drops of dishwashing soap mixed in to help apply the decals.  After cutting the decal, I dip it into the soapy water and then apply it to the body.  The soap allows the decal to slide on the body before the glue grabs.  This allows for fine-tuning the placement of the decal on the body but doesn't affect the glue from sticking once the final position has been found.  Any water under the decal is pressed out from the middle of the decal to the edge to prevent bubbles.  For bends and corners, a hair dryer on medium heat helps soften the decal slightly and activates the glue which prevents the decal from lifting.  Just press the decal into place while applying heat making sure not to get the decal or body too hot in the process.  Your fingers will be burned before damage is done to the decal in most cases anyway.

Remember the yellowed wheels?

I decided to use paint instead of chemically whitening them using hydrogen peroxide and sunlight because it seemed safer and potentially longer-lasting.  I used Tamiya TS-26 Pure White.  In the above picture, the four bottom wheels started out approximately the same color as the right-most wheel in the top row.

Here are the painted wheels with tires mounted and white lettering applied using a method that I previously posted about before:

Here are some pictures of the finished Raider:

The red color appears a bit "bright" in these photos, but in reality it isn't quite as intense.  One thing to note about the decals is that Kyosho did not specify where all of the decals should be applied in the manual, unlike Tamiya.  The major white decals were given specific locations, but the rest, such as the smaller manufacturer logos, were not specified.  I referred the to manual cover picture and box top for suggestions, but ultimately relocated some to other places according to my own personal taste.  I also omitted a few decals entirely because I thought it would become "too busy" and overwhelming.

Even though it was a fairly simple beginner's car, the Raider was a very popular basher in the late 80's and early 90's, thus making it definitely worthy of a restoration like this.

Tamiya Saint Dragon Restoration (part 2)

After almost a year and a half I finally finished restoring the Saint Dragon (58083).  The first installment of the restoration included evaluating the chassis, purchasing replacement parts where necessary and selecting some vintage hop-ups to use in the rebuild.

Because I subsequently purchased a runner Madcap chassis and just recently finished its restoration, I decided to keep the original red friction shocks on the Saint Dragon and make this rebuild more of a shelf queen.  The condition of this chassis is much nicer than the Madcap and I want to keep it that way.  The black C.V.A. shocks intended for this car went to the Madcap, however the other hop-ups, including the motor plate (53060), Thorp 48P gear set and Astute universal joints were used as I had planned. 

I followed the manual to ensure a proper rebuild, substituting hop-up parts where required.  Ball bearings replaced the plastic bushings, of course.

Here is the almost-finished chassis before the shocks and radio system were installed:

During the rebuild, the thin chassis front screw posts started to groan and slightly split, so I added some springs on the outside of the posts for reinforcement.  It helped prevent the posts from breaking further.  As I have mentioned before, these posts are one of the weakest parts of this otherwise excellent chassis.

Springs helped reinforce the weak screw posts

I used a Tamiya TEU-104BK electronic speed control with Novak 3 Amp BEC circuit (5460), Futaba R113ip receiver and Futaba S148 servo for radio gear.  The motor is an Epic Paradox 27T stock motor with 19T 48P pinion meshed to the vintage Thorp 48P gear and ball diff set. 

I have to admit I was a little bit nervous to trim the original vintage body.  I wasn't sure how brittle the plastic had become and did not want to cause an unwanted crack in the body during the trimming process.  There were already signs of stress fracturing in some parts of the body where some tight bends were located and the worst thing that could happen is for the plastic to split in those locations.

Before I started trimming the body, I decided to wash it completely using soapy water both inside and out.  Then I soaked the body in very hot water for approximately 15 minutes.  My hope was that the plastic would absorb some of the water and become slightly less brittle.  I know nylon parts can be boiled to restore their flexibility, so why not try a similar approach with polycarbonate?  I did not boil the body for fear of warping, but the water was hotter than I could handle with my hands.  I have no idea if the hot water soak helped at all, but the body did not split, crack or break during the trimming process.

Tamiya had already pre-drilled the body mount holes and the antenna hole, plus the rear vents and the inside part of the front shock cutouts were pre-cut which made trimming much easier and faster.  I used an X-Acto knife with a fresh #11 blade to do most of the trimming because it seemed to stress the body less than using lexan scissors.  Also, the body has some very deep and intricate inside corners which are extremely difficult to do with scissors.  I carefully scored a continuous line all the way around the body by following the molded-in cutout lines, then, using lexan scissors, cut the excess lexan at strategic corner points.  The scissor cuts were made in such a way that the lexan pieces could be bent along the score line and separated from the main body.  The resulting edges were amazingly smooth and as straight as the score line itself, so precision is more important than speed when scoring.  In all, it probably took about 3 hours to completely trim and sand the body.

Once trimming was finished I masked the cockpit window on the inside of the body and painted it using Tamiya PS-1 white polycarbonate spray paint (86001).  Finally, I applied a set of original Tamiya decals using the soapy water technique.

A couple decals (the gray/silver ones above the cockpit window) want to wrinkle even after completely drying and undergoing extensive heat treatment with a hair dryer and toothpick.  Not sure what can be done about that, but overall it still looks pretty good.

I remember seeing pictures of the Saint Dragon years ago and thinking how ugly the body styling looked.  As such, it was never on my list of vintage cars to buy.  But because this car was in such great condition, including the original, uncut body, I had to respect its history and properly make it into a complete Saint Dragon box art restoration.  After finishing the work, I have to say that I am glad I did.

Tamiya Vajra Built and Finished

I actually built the Vajra in early 2012 but didn't finish the body until early 2013.  The build was a good one and quite interesting, but not without some frustration at the design in some places.  I understand why Tamiya made the choices they did, I think, but I still feel like a better design for these parts I am about to mention could have been thought of for the Avante chassis (on which the Vajra is based).  I realize the basic design of the chassis is over 25 years old and fault can be found in almost all chassis designs, but for some reason some of the design "issues" I found during the build of the Vajra jumped out at me as very obvious and annoying from an engineering perspective.  Maybe I was in a hyper-critical mood during the build or something.

For the first one, in step 10 of the manual, a piece of tape is used to hold a gear shaft on the front end before a front suspension arm is mounted that blocks the shaft from coming out.  

Tape?  Really?

All Tamiya had to do was put a flat-headed screw right next to the shaft to hold it in place, similar to how suspension arm hinge pins are held in place on some modern buggies.  The shaft diameter is very thin at 2mm, too, compared to the normal 5mm Tamiya normally uses.  This, to me, seems like a design failure because compromises were made that undermine the reliability of the vehicle or at least raise serious questions about it.  Again, I think I know why they designed it that way: First, they had to allow the bevel gear (H2) to be removed quickly because it prevents the removal of the diff and they didn't want you to have to take the gearbox halves apart to do it.  Second, the 2mm shaft diameter was chosen due to the limited amount of space and bevel gear design inside the front gearbox.  Anything larger would not have fit.  But take a look at the TA-01 design, which has similar driveshaft-to-front-diff mechanics but doesn't have tape holding a 2mm shaft in place.  Sure, it has one more gear in between the bevel and diff, but seems to be a stronger design.  In my opinion, too many compromises were made in order to eliminate one gear "for improved efficiency".

Another frustration is that the front and rear outer diff joints are only held in place by the pressure of the swing shaft dogbones and the foam/springs inside their cups pushing against them.  There is no screw holding them in place, so when a dogbone is removed, the diff joint falls out.

BA25 and BA26 are only held in place by the dogbones inserted into them

No big deal, right?  I mean, other Tamiya kits have diff joints that aren't held in place either.  That's true, but at least those diff joints have a much longer shaft profile that sticks inside the differential unit itself like the ones that come with the stock Avante 2011 re-release shown here:

PB10 and PB11 fit deep inside the differential and don't fall out easily

The Vajra outer diff joints have very short interlocking protrusions that mate with the differential inner joints and they wobble as they spin under load making the whole system seem unreliable.  I am also concerned that the outer diff joints are going to wear out quickly.  Yet it's almost impossible to buy them separately.  TamiyaUSA's store is perpetually out-of-stock, not to mention how expensive they are.  After all of this complaining, I should note that I have not had the diff joints pop out at any time during many battery packs of driving.  As for wear, the jury is still out.

The wheels and tires.  Taken from the brushless powered Tamiya Super Levant (57796), I think the wheels and tires are simply too heavy for this chassis.  They make the Vajra seem clumsy.  The chassis, which is nothing more than a lengthened Avante chassis reminiscent of the Egress, wasn't designed for large truck tires.  Installing regular buggy wheels and tires, however, transforms the Vajra into a pretty nice truck.  

The adjustable turnbuckles, while having tiny hex nuts built into them which make adjustments somewhat tedious, are handy for making the necessary camber and toe-in modifications.

I know many people do not like the styling of the body, but I actually don't mind it so I won't count it as another negative talking point.  What I did do, however, was cut the front wheel wells narrower than marked in the manual since I knew from the start that I'd be using smaller wheels and tires.  The black lines in the below picture approximate the curves I followed.  Check out the pictures below of the finished body on the chassis to see the front wheel well cut outs in more detail.

Black lines show approximate front wheel cut outs I made

I highly recommend replacing the stock servo saver with the hi-torque one from Tamiya (51000).  It eliminates some slop associated with the stock servo saver making the truck more responsive.

Here are some pictures of the finished chassis with a few different types of wheels and tires mounted.

Stock wheels and tires:

Duratrax wheels and Duratrax Bandito tires:

Seben Racing BRF3 wheels and tires:

The truck uses a Futaba R113ip receiver, Futaba MC330CR electronic speed control and Hitec HS-645MG servo for steering.  The motor is an unknown brand unlabeled 19 turn double wind. 

The body was simple to paint because it was all one color: black.  I used Tamiya PS-5 Black (86005) after masking the windows.  The manual calls for Tamiya PS-31 Smoke (86031) to tint the windows but I left them clear.


Here are more pictures showing the wheel and tire combinations with the body.  If you look closely at the side decals in the pictures and compare them with the decal sheet, you'll notice that the "Vajra" text has been removed.  I strategically removed the text from the decals because I am not very fond of the name.  Due to the decal's busy lightning bolt style design, it's hard to tell the text is missing unless you know where to look.