HONDA CB750 Four K0 by yvesvidal - TAMIYA 1/6 and MPC 1/8

[yvesvidal]

I am now trying to catch up with the Tamiya kit. Assembly of the engine is in order: 

The Tamiya engine is incredibly realistic and well molded. The color is perfect without being chrome plated. The closer color is the Chrome Silver by Tamiya. Touch-ups are almost invisible.

What you see above are just the parts glued. Nothing has been done to the block yet, and no details have been added.

 

The Tamiya engine is not easy to put together and care must be applied to align the fins of the cylinders. You see way too many beautiful assembly of that kit, with mismatched fins: 

Here, I have tried to align them, by filing the space in between each fin. It is not perfect, but way better than a lot of kits you see on the Internet. Once the cylinder walls have been dirtied a little bit, it should be quite realistic.

 

After insertion (dry run only) of the engine in the frame, we can compare the two kits: 

The Tamiya kit is 1.5 times bigger than the MPC..... but it seems it is so much more.....

To take a break from the models, I am also replacing the battery on my Scale 1:1 BMW R1100S. Not exactly easy to access, but the replacement is done every 4-5 years, so it is not too bad: 

Battery has been ordered and the K&N filter washed and re-oiled:

Yves

 

 

 

 

Edited May 17, 2020 by yvesvidal

[yvesvidal]

Quick update on the MPC kit. Assembly of the Mikuni carburetors. Quite simplistic on the MPC kit, and I added some collars, using very fine soldering wires: 

The air box is clearly reminiscent of the K0 model, the early CB750 Four motorcycles. On the K1 and later models, Honda replaced that painted box with a black ribbed and less angular box:

  K0 airbox on the left and K1-K4 airbox to the right     

To simplify, MPC does not provide different size rubber hoses, as does Italeri and before them Protar. So, throttle controls and fuel hoses all look the same. 

 

Yves

 

[Gregory]

 

My 550 in '74..  Couple of my buddies had 750's..  I was jealous..

[yvesvidal]

Not much progress on the bikes, but I finished the seats. The seat of the CB750 is quite unique and very comfortable, for an early 70's bike: 

 

None of the manufacturers provided the metal decoration that goes all around the vinyl seats. I added these with a thick piece of solder, glued with Cyano-Acrylate. The MPC seat, simpler in its representation, was enhanced with two little screws of 1.8 mm to simulate the anchors of the passenger handle.

The Tamiya seat provides a real handle for the passenger, made of some kind of rubbery plastic. The Tamiya seat has a shell underneath and will open on the frame, whereas the MPC is just an hollow shell, glued to the frame.

 

Yves

 

[kpnuts]

Superb work on these.

Yes I really love these Tamiya 1/6 bike kits they are amazing.

[popeye the sailor]

bikes are looking great Yves  

[MadManSK]

Interest, a many modelars are biker boys too... 🙂

 

[yvesvidal]

Working on the carburetor ramp, on the Tamiya kit: very nice set, realistically molded although quite complex to assemble.

Parts need to be filed to allow for the glue to grip: 

And finally, some thin bands of soldering wire to simulate the clamp rings. Their respective position will be refined, once I glued the carburetor ramp to the engine. 

Here is a picture depicting the typical 4 carburetors of a 4 in-line motorcycle engine (not for a CB750). TAMIYA has correctly recreated on their kit, the cold-start operating lever. 

    

The other picture shows the main components of a traditional motorcycle carburetor. I suspect that the majority of the readers of MSW, have at least once taken apart a carburetor and perhaps try to put it back together.... 😉 As a kid, I remember filing and polishing the intake manifold of my 50 CC Derbi to increase its performance. I was then able to reach 75 KM/H, instead of the 45 KM/H authorized by law. Another aspect of the French law on Mopeds was that the diameter of the carburetor funnel could not go above 14 mm. All the young people were modifying their DellOrto carburetors with a 19 mm retrofit kit, from Italy. Highly illegal, but so exciting..... Anything was good to get a few more KM/H of top speed....

 

Yves

 

[popeye the sailor]

nice detail   

[yvesvidal]

I realized that I have not posted any progress for a while. Did not make much progress, but here you go: 

The finished painting of the various parts. Not an easy task and rather time consuming and expensive. I am using these Inspire paints which are offering a close rendering of the original Candy Gold color seen on the early CB750. These paints are from British origins (if I am not mistaken) but are available in the USA. They are expensive ($14 a bottle) and are designed for airbrush exclusively. They also require alcohol or some paint thinner to clean all your gears. 

First, you must apply a coat of Silver Fine with an airbrush. Once, you are satisfied with the silver coating, you start applying the Candy Fools gold which is almost transparent. Then you have to build up layers: at first it becomes yellowish to turn reddish after 6 or 7 coats. Take your time and be patient. My results are far from being perfect and truly, I should have practiced on spare parts, before doing the motorcycles.

After letting the whole set dry for a day or two, you need to apply the clearcoat. Here again, I ordered 2K clearcoat from the Inspire company. At $20 a can (can only be used once or twice), it quickly becomes an expensive model. The clearcoat is highly dangerous (similar to MaxSpray 2k) and comes in a special can with two tanks. By perforating the internal bottom of the can with a pin, you are mixing the two components of the clearcoat. This stuff is identical to what is being sprayed on real automobiles and you need a mask and goggles to apply it. The clearcoat in its liquid form is not really toxic, but once pulverized, the molecules of clearcoat have a strong affinity for moisture and will try their best to reach your eyes and the inside of your lungs. So, Mask with dual cartridges and fully enclose goggles. The result is quite nice and renders the metallic paint of the Honda of early 70's. The clearcoat can be polished to a perfect finish with the polish and buffing products that you use for your car. The can only be used once or twice and its shelf life (once punctured and mixed) can be extended to a couple of days, by keeping it in the fridge with your favorite beers.

 

The first thing was to assemble the front forks: 

And their headlight: 

The engines have also got some attention: Carburetors and air box: 

Notice on the Tamiya kit (picture above) how I have tried to align the engine fins. The mis-alignment is something you see in a lot of models assembled from the Tamiya kit. It is worth spending some time gluing them closely and then filing each fin so that it aligns perfectly.

On the Tamiya kit, you can see how I screwed up the top and bottom of the airbox, by not laying exactly the same amount of coats. Damn it!!

 

Finally, the frames, still trying to build in parallel as much as possible: 

 

Yves

 

 

[lmagna]

That is a fantastic looking color!

[mtaylor]

I love the candy gold you've used.   Haven't seen anyone doing candy colors in a long time.

[shipman]

Love your wheels and paint. ALL Honda's at that period had silver painted engines. Indeed there wasn't any bare polished alloy anywhere. The material was rubbish 'monkey metal' and would corrode in a blink. Handsome looking beasts at the time, but had rubber frames and a propensity to throw con-rods. Believe me, I know.

[kpnuts]

Great job, looking amazing.

[popeye the sailor]

nice!!!  

[Don Waldron]

I just came across this posting. I am going to buy the Tamiya model. I will have only one arm and one leg after paying for it!! Can you tell me if the 750 marking on the side of the bike is a molded plastic or is it a decal?

[shipman]

8 hours ago, Don Waldron said:

I just came across this posting. I am going to buy the Tamiya model. I will have only one arm and one leg after paying for it!! Can you tell me if the 750 marking on the side of the bike is a molded plastic or is it a decal?

Decal

[kpnuts]

Did these ever get finished

[yvesvidal]

On 11/25/2023 at 5:27 PM, kpnuts said:

Did these ever get finished

Not yet. Too many other projects....

 

Yves