Roller Coaster 10261 chain smoothness issue

[Bigcting]

My son just finished the roller coaster, the only problem is that the chain doesn’t move smoothly. When I crank the links at the the top between the tires (counter clockwise) everything runs in the right direction, it’s just very difficult to move. I have seen video and I know that Lego makes sure there sets work, but for the life of me, I can’t figure out what’s wrong. Any help suggestions would be appreciated.

[Johnny1360]

Not sure, I do know I was at the LEGO store right when they had just finished building the display model and I got to mess around with it a bit. The crank seemed to catch every now and then and was difficult to turn at times, I just figured the employees did a rush job and didn't take care to make sure everything worked smoothly before continuing the build. Now I am starting to wonder if it isn't something else, seems as though many people are having issues with it. Some seem to solve the issue by removing a link or two out of the chain. 

I will say though, there is a lot going on with that mechanism and it is quite large, so I would take extra care to make sure everything works smoothly before moving on to the next stage. At least that way you could identify wherein the problem lies. 

[VBBN]

From my experience in owning this set two issues I ran into were;

1) Make sure every axles is free to spin as easily as possible. If you push pieces too tightly together when assembling these technic constructs, resulting in axles have a bit of friction when they try to rotate, it's going to cause major issues in the final mechanism.

2) Does changing the amount of links make any difference? Lego purposely gave an extra amount of links with this set as everyone's set will function differently, some people may need 200 links while others may need 205. 

I had some issues with both of these and at first it completely messed up the function of the coaster. 

[1963maniac]

Sorry this is so late. I have been working on a MOC. The parts orders take so long to get here then you find out you needed something different. Then you order again, and you do that seven times and still more is needed.  Anyway, the problem is with the wheel mechanism that brings the coaster around the half circle at the top. If that system is disengaged, everything will run smoothly. But obviously you need the coaster to go around up there, whether you crank or power it.

Some MOCs use a 24738 track immediately following the chain and they do not use those wheel mech's at all. However this requires a redesign. I developed some work arounds that have increased the speed of the chain and wheel mech and cuts down on gear friction. That idea helps a lot but still is jerky and slows down. I am now thinking about powering the wheel mechs separately from the chain mech.

[1963maniac]

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