[MOC] Pullback Motorcycle

[Hedgie]

Something different for a change: I used two Lego pullback motors to create a V-twin engine for a minimalist, all-black motorcycle.

Beneath the engine is a 2-speed gearbox. The lever on the right selects between 1st gear (down position), neutral, and 2nd gear (up position).

It also features working suspension, steering, and a kickstand.

The pullback motors provide enough power for doing some sick burnouts, but not enough to ride the motorcycle for any meaningful distances. Also, being a motorcycle, it falls over as soon as you let go. I added a simple steering lock to improve the playability a little (see the final page of the instructions).

Both the building instructions and LDraw source can be downloaded for free on my website: https://jj.created.today/pullback/ While you're there, also check out my other models!

I hope you like it!

(Some further information: I used LDCad to create the MPD file. Its "closed triangle" feature was invaluable to calculate all the correct angles. The instructions were created with LPub3D and the images were rendered with POV-Ray.)

Edited March 25, 2021 by Hedgie
grammar

[amorti]

That looks brilliant!

As shown in this thread, it is possible to get a Lego bike to stand up.

Not sure if the high CoG would present an issue to that.

I think the trick is to build in LOTS of trail, not necessarily by having cruiser-like rake angles, but by mounting the fork behind the steering axle.

[jorgeopesi]

Good idea and very nice bike  .

[that_lego_builder]

3 hours ago, Hedgie said:

Something different for a change: I used two Lego pullback motors to create a V-twin engine for a minimalist, all-black motorcycle:

can you make a bike with the system motors

Edited March 25, 2021 by that_lego_builder
Removed block of text and pictures.

[Milan]

@that_lego_builder We have been through this, but once again: please use proper capitalization and punctuation, and read and follow the site guidelines (do not quote the whole block of pictures).

[that_lego_builder]

1 minute ago, Milan said:

@that_lego_builder We have been through this, but once again: please use proper capitalization and punctuation, and read and follow the site guidelines (do not quote the whole block of pictures).

oh sorry bout that 

[Hedgie]

3 hours ago, amorti said:

I think the trick is to build in LOTS of trail, not necessarily by having cruiser-like rake angles, but by mounting the fork behind the steering axle.

It's not lack of trail, it's lack of torque. Even in first gear, the Lego pullback motor cannot produce the torque needed to create any kind of balance. Besides, a sports motorbike needs a steep rake even if only for its looks. I should really post a video though about its sick burnout capabilities, it's MADE for it. However, I don't have the means to produce good video, so I'd rather not make one at all.

[Johnny1360]

Good job coupling two pullbacks, and I think it definitely has some potential.

I also think it looks pretty good, with minimal parts, less is better with pullbacks.

 

[Ivorrr]

That would definitely be a contender in the last TC for motorbikes! 

That thing looks neat!

[Hedgie]

On 3/26/2021 at 11:23 PM, Ivorrr said:

That would definitely be a contender in the last TC for motorbikes! 

That thing looks neat!

OMG, how could I have missed this contest! The bike was mostly done before February. I just postponed posting it until I had the building instructions fully done

 

I wonder what the winning bikes look like. I checked this topic but I couldn't find any photos or links to the winning entries...