I am building the Harley Davidson Fat Boy from Creator Expert (10269) and when installing the chain belt that connects the engine gears to the rear wheel I noticed that it runs quite jolty, with the chain links feelably and hearably clicking onto the gear when running over it. It all feels like it doesn't quite fit and run as smoothly as it should.

However, I don't have much experience with chain belts in technic constructions, so I don't know if this is maybe a general shortcoming of LEGO or if I just made a mistake somewhere. I did closely follow the building instructions of course and I also checked that I use exactly the 43 chain links mentioned as well as aligned the chain in the direction depicted. Or maybe it has to run this way and this is an intended effect for a "rougher" or more pulpable engine feeling?

So I'm basically just trying to check if I built it correctly and it does run kind of jolty or if it has to run smoothly and I made a mistake somewhere.

  • Just took out my model and I would not describe the chain as super smooth but certainly also not as you are describing it. Audibly, the fake engine and gears makes much more noise than the chain. On the other hand, can't really think what you might possibly have done wrong if you counted the links and aligned the chain properly... Jan 23 '20 at 22:09

Okay, it seems I indeed made a mistake during building, which I solved afterwards:

When assembling the rear mudguard, I noticed that the rear wheel had quite a bit more variability in its sideways adjustment and was quite a bit off center, specifically too far to the left. This caused the chain belt to either run slightly skewed or have friction on some part of the frame. When I adjusted the wheel more towards the center, it ran a lot smoother.

However, this was only part of the problem. The actual mistake I only realized at the end when seeing a little yellow half-stud wide technic bush, which I missed in instruction step 25 already, where it was placed under the gear on which the chain runs and is supposed to space it further away from the frame. Fortunately I was able to repair that without dismantling the entire thing.


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