My son (age 9) has been working on the Bugatti Chiron and ran into trouble at step 490 attaching the blue piece to his existing gearbox. There is a gap where the new piece is supposed to get locked into place. It appears he did something wrong at some point with the gearbox. Any advice on where he might've gone wrong and how we could fix it without having to start all over? See pictures for more detail. 

That's a tough one, there are a lot of steps coming together here and i can't find any obvious errors on your pictures. Could you please provide a picture of the underside?

Thanks for giving it a look! I've attached a pic of the underside and another shot of the top with an additional gap circled. From the top it looks like the two pieces haven't been fully connected, but it doesn't seem from the bottom that there's anything that can be pushed together any further. 

My model was also being a bit weird at first, but there were no problems with the end result.

I took a few parts from my Chiron to check the same place - it seems that the part of construction where the pin is is offset one stud to the back in relation to the blue beam that it is supposed to connect to. But taking into account complexity of this model it is almost impossible to find the problem remotely. I guess that comparing the build with the instruction is your only option to find the error :( Not sure if this is any help but here is the picture from my model:

Blue lift arm is too short/located 1 stud closer to the front. Second thing, look at the engine, the right side, do you see something wrong? :D

9 hours ago, andrzejl said:

I took a few parts from my Chiron to check the same place - it seems that the part of construction where the pin is is offset one stud to the back in relation to the blue beam that it is supposed to connect to. But taking into account complexity of this model it is almost impossible to find the problem remotely. I guess that comparing the build with the instruction is your only option to find the error :( Not sure if this is any help but here is the picture from my model:

Thank you so much for checking yours and confirming that we were off! I guess we just have to go back and check everything. He's not going to be so happy about that, but at least I know now that we're off. 

2 hours ago, mflavel said:

check everything

I suggest to check around step 465, here's the most potential for difficulties.
Best of luck solving that puzzle!

 

Unfortunately i can't see your pictures, they seem to be dead links.

Oh, sorry about the photos! I've fixed the links. Thanks for the tip about step 465! We'll start by looking at that. 

Just a tipp: The upper right cylinder bank faces the wrong way...

Oh, thank you for pointing that out!