[TC30] Motorcycle & Engine

[JoKo]

I love motorcycles and my fist technic set was the 8838 motorcycle back in 1991. And today...

The idea is to build a mid-size motorcycle (75mm wheels) based on a real one, and build a detailed model of it's engine. Motorcycles like the "small" Ducati and  Kawasaki h2r  are ~400g so I need do do something simpler. Ideally a motorcycle without heavy fairing, with an interesting engine (with a valvetrain). My choice is the HONDA RS750, a racing flat track motorcycle from the 80's. Flat track (or dirt track in Europe) is racing on an oval track made of smooth dirt. This sport is mostly popular in the USA but I was lucky enough to give it a try in a small swiss event. Definitely one of the most thrilling experience I had on two wheels! 

 

The bike:

The wheels used on flat track motorcycles are bigger than the standard road bike wheels. That helps me keeping the scale small (~1:7). Because of this scale I won't be able to fit a gearbox in it. 

Features:

• Front /rear suspension
• Chain driven V-twin fake engine
• steering obviously
• curent state: 275g.

 

 

 

 

 

Fake engine:

The scale will be around 1:3 or 1:3.5 with a 3 studs bore and 2 studs stroke.

I gathered technical informations about the engine developed for this motorcycle and there are the  points that I want to replicate:

• 45° V-twin 
• 90° offset crankshaft
• chain driven SOHC (single over head camshaft)
• 4 valves per cylinder

I found a forgotten prototype for a "similar" fake engine and modified it to serve as a proof of concept and weight approximation. it only fits the SOHC aspect but that's a starting point. I'm thinking about making it motorized with buwizz 2.0. It's around 310g if I count for the buwizz.

 

 

That's it for now.

Curious about flat-track? https://youtu.be/cy4koDhiAB0?si=JkBe84C3bZUSbpdJ

Curious about the Honda RS 750? https://youtu.be/jWpLIp6HD34?si=lbb3_tUdbqYPVmXC

 

[bruh]

Very interesting! The bike looks accurate. The engine looks sick and intricate. Where would the motor for the engine be? Just on the back to drive it?

[2GodBDGlory]

Cool ideas, and nice progress! I think I've been underestimating how much 300g is, now that I see these builds!

[JoKo]

2 hours ago, bruh said:

Very interesting! The bike looks accurate. The engine looks sick and intricate. Where would the motor for the engine be? Just on the back to drive it?

Thank you! The motor is in the base of the prototype and probably stay here in the final model

9 minutes ago, 2GodBDGlory said:

Cool ideas, and nice progress! I think I've been underestimating how much 300g is, now that I see these builds!

Thanks! I kept the tires weight low  

[bruh]

2 hours ago, JoKo said:

Thank you! The motor is in the base of the prototype and probably stay here in the final model

Are you using the micro motor?

[JoKo]

 

I don't have smaller than PF M and I think it would be too slow with a less powerful motor

[bruh]

I only looked at it quickly, it the micro motor is quite strong; I don’t know if it would be enough, but it has power!