Something different: Scratch-built 1/12 Scale Evel Knievel HD XR-750

[PVmodels]

Not sure how many of you will be into this subject but you might appreciate it from an artistic perspective. In addition to Star Wars, I'm into 70's and 80's pop culture, toys, etc. My brother and I had Evel Knievel stunt cycles growing up. I have restored some of our originals and purchases other vintage Knievel toys. I've also been building model cars for many years. I decided to build a MPC model of the Fonz's Triumph motorcycle. The kit was so toy-like, I ended up scratch building a lot of extra parts from plastic and metal. I built so much for it that I started to question...could I build an entire Evel Knievel HD XR-750 from scratch? You guys with 3D printers are probably going to shake your heads at the amount of effort I took to basically be a human-3D printer. I started by printing a side photograph of the motorcycle in scale with a donor set of tires and rims.

I measured and calculated parts to scale. One of the biggest challenges was figuring out how wide things should be. I spent a lot of time searching for real XR-750 parts and bolts in order to calculate the frame width, the engine width, the tank/seat width. I started with some of the easier parts like the cover below the exhaust. This is multiple layers of plastic sheet glued together and then carved and sanded to the correct shape. The chrome part was then covered with bare metal foil.

I cut all the molded spokes out of the donor wheels and hand laced them with 0.3mm stainless steel wire. I also made the front fork out of aluminum tube and plastic layers for the connecting parts.

Next post, I will show building the frame and then the insanity of scratch building the engine.

 

[PVmodels]

The frame: The backbone of the entire build and it is made almost entirely from plastic rod. One piece of aluminum tube was placed where the gas tank goes because this piece needs to retain it's shape. The rest of the frame is held in shape by tension.

The engine: Here is where things get crazy. I built a shell for the bottom end of the engine and then made everything else from layers and layers of plastic sheet.

All the nuts you see around the engine are hex shaped rod added for detail.

 

[PVmodels]

First time on 2 wheels: Sorting out the rear suspension and wheel location.

Bending the aluminum rod for the handlebars. Making the front brake and brackets.

Test fitting has gone well. Finally time to start painting and assembling. Added the aluminum exhausts. Made the levers from 2 layers of plastic sheet and shaped them with an Exacto and files.

 

[Bloop]

That's crazy-good! Your attention to detail is outstanding, like redoing the spokes by hand. Even though I've been 3D printing myself, I'm still impressed by anyone who has scratchbuilding skills. And I also grew up with the Evel Knevel stunt cycle. Looking forward to how this turns out.

 

[PVmodels]

That's crazy-good! Your attention to detail is outstanding, like redoing the spokes by hand. Even though I've been 3D printing myself, I'm still impressed by anyone who has scratchbuilding skills. And I also grew up with the Evel Knevel stunt cycle. Looking forward to how this turns out.

Thanks! The spokes were tedious to do. I used a 0.5mm pin vise drill bit to makes holes in the rim and in the hub. Each spoke is j-bent at the hub end to go in the hole. Crazy glued on each end. Eyes got tired after a while. Did the same on the Fonz’s motorcycle. Between the 2 bikes that was 144 spokes.

 

[PVmodels]

The gas tank and seat: I should have counted how many layers went into the various parts. The tank has many layers. The outsides are layered and then there are 2 layers in between them to make it three dimensional. Getting the tear drop shape required a lot of filling and sanding.

The fender which would have been fiberglass or plastic on the real motorcycle was easier to make. It was just a fancy shaped, 3-sided box.

The seat was more complicated. The inside of the seat is 2 layers of cardboard with carved edges. I used recycled, red vinyl from an old binder to cover the top of the seat. The sides are made of white vinyl that was spray painted blue. The real cycle had a painted seat. You can see black through on one of the original cycles. The white piping was done with very thin plastic tubing that is Krazy glued to the vinyl.

 

[starks]

Mate, just an exceptional amount of detail there. A perfect example of how you can just about make anything!

That layering plastic and shaping is a good trick, I did the same thing creating the turret domes on the sides of my At-At head. I cheated and laser cut shapes though, you must have really spent some time cutting all these shapes from styrene. Especially the fins for the heads.

Lovely work, realistic painting, love the respoking of the wheels.

Were you able to steal the carburettors off something else or have you scratch built those to?

Cheers,
Josh

 

[PVmodels]

Mate, just an exceptional amount of detail there. A perfect example of how you can just about make anything!

That layering plastic and shaping is a good trick, I did the same thing creating the turret domes on the sides of my At-At head. I cheated and laser cut shapes though, you must have really spent some time cutting all these shapes from styrene. Especially the fins for the heads.

Lovely work, realistic painting, love the respoking of the wheels.

Were you able to steal the carburettors off something else or have you scratch built those to?

Cheers,
Josh

Some of the pictures showed how the engine fins were done. I made a big template and a small template, traced them, and cut them individually. Then glued big, little, big, little..then some filing and shaping to line everything up.

The carbs are built from styrene sheet and tube and some aluminum tube. The only donor parts are the outer rims, tires, and part of the chain.

I’m fortunate to have a fantastic hobby store near me. All the plastic and metal for this came from them. And I also bought every variety of metal spray paint they had to match the different real materials.

 

[PVmodels]

The finished product: I replicated as much as I could. Probably one of the smallest details are the springs that go from the oil tank under the seat to the frame. The springs are single strand of speaker wire that I wrapped around 0.3mm steel rod. I also made the quick-lift stand Evel’s crew used to hold the bikes. It was a satisfying project and there won’t be another just like it anywhere.

 

[starks]

Some of the pictures showed how the engine fins were done. I made a big template and a small template, traced them, and cut them individually. Then glued big, little, big, little..then some filing and shaping to line everything up.

The carbs are built from styrene sheet and tube and some aluminum tube. The only donor parts are the outer rims, tires, and part of the chain.

I’m fortunate to have a fantastic hobby store near me. All the plastic and metal for this came from them. And I also bought every variety of metal spray paint they had to match the different real materials.

Your attention to detail is astounding. A very rewarding project!

Cheers,
Josh

 

[PVmodels]

Famous motorcycles of the 1970’s:

 

[dynasoar62]

Verry Nice