[MOC] 1:8 Custom Harley Chopper (motorcycle)

[gheneli]

This is a 1:8 scale custom Harley CHOPPER (motorcycle)

 

It features a visually impactful 2-speed gearbox, using two chains (gold and black) that move at different speeds depending on the selected gear, all while being connected using a shared (yellow) axle.

This is very close to how a real Harley transmission works, and it was the main thing that made me design this bike in the first place, as I haven't seen anyone use this type of dual-chain gearbox before.

The gear selector uses the old style switch, so it doesn't require a 90 degree rotation to shift, as is the case with the relatively recent Lego bikes (such as the 1:8 scale Ducati or Kawasaki sets), making it more accurate to how the real bike shifts gears. I also think it's pretty annoying, visually, to have the lever turn 90 degree for shifting, so I'm pretty happy with this one.
The shifter also works perfectly fine 100% of the time, after I switched the old style tow ball + connector assembly with the new style connector. For some reason, it seems to have more grip and more force to shift properly. The old one would fail sometimes, being unable to shift, no matter how much you pull the lever.

Gear ratio:
1st GEAR (down) - 1:1.6 - gold chain moves 1.6 times faster than the black chain
N (middle) - gold chain doesn't move
2nd GEAR (up) - 1:1 - gold chain moves at the same speed as the black chain

 

The second feature I'm proud of is the suspension.
And, while the springer fork (front) shouldn't feel like such an outstanding achievement, the rear pullrod system certainly is. The modern chopper designs tend to hide their rear shock absorber to replicate the classic rigid / hard tail style bikes, while offering the comfort of a modern bike.
Initially, the idea was to use a simple hard spring under the seat, but I couldn't properly fit it, so I ended up positioning it under the frame. That came with a problem, because now that the suspension assembly is underneath, it has to pull the spring, not push it. So, I had to design a whole pullrod system. I'm using a wishbone from the 2025 Technic Formula 1 sets to connect the swingarms to the spring assembly, and I'm very happy with the final results. I think it has a very clean, satisfying look.

 

The real difficulty came from the fact that I wanted the swingarms in a perfectly horizontal position when in neutral, mainly because the pivot attaching to the frame could not move too far, because it was positioned just one stud away from the frame, so I had to position it vertically, to make sure I could get full range of motion from it.
This position was made difficult by the design of the spring itself, which is 6,5 long, for some reason still unknown to me. That meant I had to attach the spring at a half-stud on the rear side, so that it wouldn't be forced to stay half-stud compressed at all times (because I really believe keeping the spring compressed at all times will eventually damage its range).
I can tell from experience that designing a strong half-stud attachment is quite hard, especially in a tight place. So, the solution came with the engine block connector. Imagine my satisfaction when I realized I could use a single connector to solve my half-stud issue, while also helping make the frame sturdy because of all the attachment points this connector has available. 

 

 

The third and the most fun challenge was solving the frame geometry.
I wend crazy with this one, as every single attachment point on this frame is a strong, sturdy one. None of the parts can rotate or move once attached to the frame. I especially wanted to use those links in the front (the A pillar links from the P1 set) as, again, I haven't seen any chopper design use those, and it's a pity because they're absolutely perfectly creating the iconic triangular front supports. The only problem was fitting them in the right position. 

 

Below you get to see my thought process when designing the frame geometry. Basically, starting with the Pythagorean triangle rule and extending from there. See how you can combine multiple triangles of various sizes. Either that, or the mirrored triangles principle.
This below is not the final version, but an older frame prototype. Still, the applied principle remains the same.

 

The rest of the features include:

• ~50 degree turning / steering radius
• V-Twin engine with working pistons
• brake disks with calipers and front brake cable
• simulated brake pedal using rubber connector (right side)
• indicated ignition switch, oil tank, oil radiator, air filter and ignition coil with sparkplug cables (which you can't see here because I'm still missing 2 antenna pieces)
• kickstand

 

 

Instructions are available on Rebrickable

Thank you for reading till the end! If you like this design, I'd appreciate a share! It seems very few people engage beyond a generic comment nowadays.

[2GodBDGlory]

Hey, nice work! I like the use of non-standard techniques. The rear suspension is pretty interesting, and the use of the engine mount part back there is fun! The front suspension is also fairly interesting. The use of those A-pillar parts is very nice too! I also like the inverted engine blocks!

[gyenesvi]

I'm not much of a bike guy, but it looks very cool, and has some solid geometric solutions too!

[1980SomethingSpaceGuy]

Hi @gheneli!

Very nice bike you have here. I love motorcycles and we definitely don't have enough around... 
I especially like the creative solutions in your MOC; inverted cylinder bricks, rear suspension and I think the gearbox with a efficient 1-N-2 is neat.
Modern gearboxes with steppers and more gears tend to take too much space for such a naked bike.
Part usage for the fuel tank is spot on.

I'm not a huge fan of choppers myself, but I like their aesthetics and yours work really well.
I think you could skip the mirror and one lever to get even slicker with no compromise to what's done with actual chopper builds, but that's just my humble opinion.

Anyway, welcome to Eurobricks and congratulation on this beautiful MOC!

[jorgeopesi]

Very nice chopper with a lot of technic details. I am not a fan of bikes but when something is awesome I have to say It.

[gheneli]

2 hours ago, jorgeopesi said:

Very nice chopper with a lot of technic details. I am not a fan of bikes but when something is awesome I have to say It.

Thanks, yes, same here, I'm not a fan of bikes (I've never driven one) but they actually look very cool on display and this one is made with that thought in mind, especially with the suspension idea and the visible transmission.

 

18 hours ago, 1980SomethingSpaceGuy said:

Hi @gheneli!

Very nice bike you have here. I love motorcycles and we definitely don't have enough around... 
I especially like the creative solutions in your MOC; inverted cylinder bricks, rear suspension and I think the gearbox with a efficient 1-N-2 is neat.
Modern gearboxes with steppers and more gears tend to take too much space for such a naked bike.
Part usage for the fuel tank is spot on.

I'm not a huge fan of choppers myself, but I like their aesthetics and yours work really well.
I think you could skip the mirror and one lever to get even slicker with no compromise to what's done with actual chopper builds, but that's just my humble opinion.

Anyway, welcome to Eurobricks and congratulation on this beautiful MOC!

Thank you!
I had a lot of fun with all these details, especially considering that I've started this design thinking there's no way I could manage to solve all of these. Two months later, here I was designing the instructions, making sure everything is great, the process is nice, fluid, nothing repetitive or boring, sturdy, without parts of the assembly wobbling around. Had 3 of my friends come in and test-build it. Yet no one is interested in buying it, so it all feels kinda pointless, haha. I wasn't expecting any miracles, but 1 single sale for such an interesting model (at least in my opinion) is super frustrating. Might as well offer it for free, much better than keeping it in a dark corner where no one can see it.

 

23 hours ago, gyenesvi said:

I'm not much of a bike guy, but it looks very cool, and has some solid geometric solutions too!

Thanks! I wonder where the bike guys are, I can't seem to find any chopper fans.

 

On 2/1/2026 at 1:01 AM, 2GodBDGlory said:

Hey, nice work! I like the use of non-standard techniques. The rear suspension is pretty interesting, and the use of the engine mount part back there is fun! The front suspension is also fairly interesting. The use of those A-pillar parts is very nice too! I also like the inverted engine blocks!

Thanks! I appreciate it when people actually notice all the details that I've spend a lot of time thinking about.

[TeamThrifty]

I own 3 bikes, all japanese sports bikes so i'm not a harley fan but i am a lego fan - This bike captures the real thing very well indeed. (I've ridden one once and i suspect that this lego version is better built and probably handles better! The real thing was awful...)

Lego can't offer the forked conrod (terrible engineering solution to a problem that doesn't exist) that allows HD's to have both cylinders on the central axis... But does have staggered bigends instead, so looks authentic! 

The difficulty with bikes is capturing the stance and you've achieved it wonderfully. This is why mocs are better!

[mahjqa]

Thank you for the thorough explanation of the features- this is all very insightful!

It's a gorgeous model, and it was great to learn about the design and features. 

[1980SomethingSpaceGuy]

2 hours ago, gheneli said:

Thanks! I wonder where the bike guys are, I can't seem to find any chopper fans.

I own four motorcycles and ride them a lot; on and off-road. So I consider myself a bike guy.
But you know; most motorcycle enthusiasts outside of the US are not that much into choppers, which may be difficult to legally register, are very expensive and basically only good at looking nice and driving straight on a flat road.
I guess people geeky enough to enjoy building Technic while at the same time enjoying the inherent inefficiency of a chopper is rather niche...
Still, it's a motorcycle MOC (and a beautiful one), which we don't see enough here, so you have my full support!

[flyingpancake]

1 hour ago, TeamThrifty said:

I own 3 bikes, all japanese sports bikes so i'm not a harley fan but i am a lego fan - This bike captures the real thing very well indeed. (I've ridden one once and i suspect that this lego version is better built and probably handles better! The real thing was awful...)

Lego can't offer the forked conrod (terrible engineering solution to a problem that doesn't exist) that allows HD's to have both cylinders on the central axis... But does have staggered bigends instead, so looks authentic! 

The difficulty with bikes is capturing the stance and you've achieved it wonderfully. This is why mocs are better!

In my whole life, the closest things to motorbikes I have ridden are bycicles, but I have seen a few choppers on the highway and i can imagin that position would be really uncomfortable!

[gheneli]

55 minutes ago, mahjqa said:

Thank you for the thorough explanation of the features- this is all very insightful!

It's a gorgeous model, and it was great to learn about the design and features. 

I'm happy you found it useful!
 

44 minutes ago, 1980SomethingSpaceGuy said:

I own four motorcycles and ride them a lot; on and off-road. So I consider myself a bike guy.
But you know; most motorcycle enthusiasts outside of the US are not that much into choppers, which may be difficult to legally register, are very expensive and basically only good at looking nice and driving straight on a flat road.
I guess people geeky enough to enjoy building Technic while at the same time enjoying the inherent inefficiency of a chopper is rather niche...
Still, it's a motorcycle MOC (and a beautiful one), which we don't see enough here, so you have my full support!

Yeah, I don't think it's about actually owning a chopper in order to enjoy a Lego toy that sits on your shelf. I've never ridden one and I don't care about the ride position, comfort or how much money it costs. All I care is it's an amazing build, it looks good on my shelf and has interesting functions to show when friends come over. On top of that, it's a 650 piece build, and the only actual rare part is the rear tire + rear wheels so I call that pretty accessible, price wise. I tried optimizing the part lots, so I don't use different color parts unnecessarily.

I don't really get this "it's too niche for people to be interested" thing. I'd be interested in many things that are well designed out of Lego, even Creator, and I'm not a Creator designer. I bought the medium size Millennium Falcon because I thought it looks really cool for display. I'd buy tanks, fighter jets, all sorts of bikes. That doesn't mean I have to own or drive a tank, or pilot a jet to be able to enjoy a beautiful piece of design and engineering.

That's probably what drives me to design Lego, the human ingenuity behind some of the existing vehicles. That's what we should appreciate first, in my opinion.

[1980SomethingSpaceGuy]

I totally agree with you, my friend. Indeed, one does need to have an actual crane of their own to be interested in building one out of Lego.
Yet it's not the first time I see that motorcycles tend to draw less attention on EB than their 4 wheeled counterparts.
Maybe the fact that most Lego motorcycles used to be rather straightforward in terms of mechanical complexity...

My point was: don't blame your design, it's really good.

Edited Monday at 04:26 PM by 1980SomethingSpaceGuy

[2GodBDGlory]

3 hours ago, 1980SomethingSpaceGuy said:

Maybe the fact that most Lego motorcycles used to be rather straightforward in terms of mechanical complexity...

That's fair; when I see a motorcycle MOC, I expect to see suspension, steering, an engine, and likely a gearbox, and it's very unlikely to see anything else for functionality. There can definitely be nice techniques, as in this model, but there's never really any question to me about what interesting functions there might be

[TeamThrifty]

19 hours ago, gheneli said:

I don't really get this "it's too niche for people to be interested" thing.

me neither - BWE is an excellent example. Its theoretically not my kind of thing, but i saw builds of it, liked it, bought it and built it and absolutely loved it! Its one of my favourite sets. Niche is meaningless, these sets need to be released and people will actually love them regardless of preconceived  ideas. Unfortunately we're in era that totally the opposite, no variety just car-coma play it safe sets.

[1980SomethingSpaceGuy]

2 hours ago, TeamThrifty said:

I don't really get this "it's too niche for people to be interested" thing.

Yep, it's definitely not how I feel about MOCs; I like all sorts.
But it's a fact. Cars generate more views, comments and, ultimately, sales. It's even noticeable here. TLG, as profit-based company, just follows the trend.
We often complain about their marketing choices but they only reflect the actual market.

That's why I design MOCs as a hobby and why I like EB; this community shows interest for any type of contraption and I'm happy to share and build, away from commercial concerns.

[TeamThrifty]

1 hour ago, 1980SomethingSpaceGuy said:

and why I like EB;

There's less mocs on display here than there used to be, which i find strange. I'm 99% mocs, have been since i was 8 in 1980... ...I mainly look on here for news of new sets and the rare good moc. But its getting rarer,

[SeptemLego]

This looks awesome! I think I will buy your instructions I build it with my son! I do own a real Harley but she is not chopped ;).

[1980SomethingSpaceGuy]

9 hours ago, TeamThrifty said:

But its getting rarer

May be.
But anywhere else, it's just static images. Here, human interactions still are a thing.

[gheneli]

On 2/2/2026 at 6:16 PM, 1980SomethingSpaceGuy said:

Maybe the fact that most Lego motorcycles used to be rather straightforward in terms of mechanical complexity...

I mean, if we're talking about a display model like the P1, compared to a bike, what else does it have? Steering, suspension, a gearbox, this is basic and both have them, then the opening doors (I guess... which a bike doesn't have) and the raising spoiler, which is nice, sure, but nothing crazy complex. So, I'd say both of these are meant to do well on display and most points go to esthetics.

The P1 gearbox is a lot more complex that anything you'd be able to put on a bike, true, but for me, it feels pointless, especially when you have no idea what gear you're in, not to mention it jams sometimes and fails to shift, and on top of all that it takes a lot of space and limits the details you can add to the engine. And, damn, that's a beautiful looking engine on a P1. I'm especially referring to that godawful way of representing the gold pipes using those sloped bricks, damn I was super disappointed when I saw that. The big 2x2 round elbow pieces would've been fantastic for those pipes, but I guess there was no room because of all the crazy gearbox taking up all the space.

I understand some people like to build crazy mechanisms that don't do much in the end, but if you're building a display piece and you sacrifice important details from the engine just to put on a gearbox nobody is gonna use more than once, it just feels weird to me. At least on my chopper bike you can see the 2 different chains move at different speeds, it's a joy to go shift gears and see how the chain changes move speeds. 
I think that's what we're missing nowadays, be able to see the mechanisms in action, see the pistons moving, not cover them like they do in some sets, the G Wagon, for example.

 

On 2/2/2026 at 10:17 PM, 2GodBDGlory said:

That's fair; when I see a motorcycle MOC, I expect to see suspension, steering, an engine, and likely a gearbox, and it's very unlikely to see anything else for functionality. There can definitely be nice techniques, as in this model, but there's never really any question to me about what interesting functions there might be

As I was saying above, I don't think you expect a high number of complex functions from a set like the P1 (except for the crazy gearbox - even though it COULD'VE HAD adjustable suspension, which would've been really cool to see when going into race mode the spoiler raising and ride height lowering), or Ford GT / GT40? Or even the Rexy set, it has the integrated jacks, but that's about it, not even a simple gearbox. So then why is a motorcycle viewed as less interesting or having less expectations from it?

And then, if you're comparing a utility vehicle, like a crane (that has a crazy amount of movable parts and functions) to a display set like a racecar, I don't think that's a fair comparison, these should be into different categories. 

 

On 2/3/2026 at 12:20 PM, TeamThrifty said:

Unfortunately we're in era that totally the opposite, no variety just car-coma play it safe sets.

Yeah, that's a corporation for you, always playing it safe because they have to go for profit first. Seeing they're releasing yet another Technic F1 set is super disappointing to me. Also, that orange recolor for the tuxedo cat, how lazy can you get?
That's why I think we need more good MOC designers, to compensate for what TLG is afraid of doing.

 

23 hours ago, 1980SomethingSpaceGuy said:

That's why I design MOCs as a hobby and why I like EB; this community shows interest for any type of contraption and I'm happy to share and build, away from commercial concerns.

Yeah, I realized I'd never be happy if I didn't share my designs and just built them for myself. Sharing seems to be a very important part. And yes, I'm probably gonna do the same, I'd absolutely hate designing something just because it's a trend now. Actually, I'd probably even go the opposite way of what the trend is. We're missing a lot of vehicle types, and I'd love to fill that gap, like a backhoe for instance, I haven't seen one from Lego in ages, except for that 10$ mini set, which I can't really count in.

 

16 hours ago, SeptemLego said:

This looks awesome! I think I will buy your instructions I build it with my son! I do own a real Harley but she is not chopped ;).

Happy to hear! I lowered the price as well, since I don't think I'm gonna become a millionaire yet from selling these, haha, but I don't want to give them away completely free either, since I have a belief that people don't usually appreciate free things and take them for granted.
If you build it, I hope you enjoy the process and hope you can share your thoughts here, what you liked / didn't like about it. 

 

13 hours ago, 1980SomethingSpaceGuy said:

May be.
But anywhere else, it's just static images. Here, human interactions still are a thing.

I noticed that, too. I rarely get any comments related to the building technique or a certain part usage outside of EB, only the usual "great job!" types.
I'm actually pleasantly surprised by the interactions happening here.

[1980SomethingSpaceGuy]

47 minutes ago, gheneli said:

The big 2x2 round elbow pieces would've been fantastic for those pipes, but I guess there was no room because of all the crazy gearbox taking up all the space.

I totally agree with you on that. Motorcycles used to be simpler in TLG's range, so I was just making an hypothesis as to why they don't catch as much public attention as cars.
One could argue that car suspensions have come a long way and are more interesting than a motorcycle's but I'd say; first, it's mostly due to dedicated parts and second, creative suspension systems can be implemented for motorcycles too, your MOC above being a perfect example.

On a side note, I totally agree with you about recent car gearboxes; I absolutely don't get the trend to implement a gear bonanza taking up all the inner space for just one feature that is too often unreliable and offer absolutely no more play feature that a 1-N-2. Moreover, their mechanical implementation being so far away from an actual gearbox.

I hope you’ve had the chance to recover from the negative feelings this experience have brought, and that you will continue to find happiness in your design work.

[2GodBDGlory]

1 hour ago, gheneli said:

As I was saying above, I don't think you expect a high number of complex functions from a set like the P1 (except for the crazy gearbox - even though it COULD'VE HAD adjustable suspension, which would've been really cool to see when going into race mode the spoiler raising and ride height lowering), or Ford GT / GT40? Or even the Rexy set, it has the integrated jacks, but that's about it, not even a simple gearbox. So then why is a motorcycle viewed as less interesting or having less expectations from it

I think the difference is that I'm thinking in the MOC world rather than the set world. I don't expect Lego to do anything more interesting with their cars than their motorcycles, but when we're talking MOCs, I think the upper limit on complexity is higher for cars than motorcycles, so I can always hope that when I see a new car MOC, it'll have more going on.

I'm also not someone who really has much interest in building stuff to display, so I guess the MOCer in me just likes to see mechanical flights of fancy, even if they compromise other aspects of the model