I think I read somewhere that the pipe from the carb to the airbox needs to expand 30% per foot or something like that in order not to be restrictive to the intake tract. Thats why the BBR U turn thingy gets bigger as it gets closer to the filter. Ask Dood.
looks good, not trying to hijack but im going to ask im picking up an x4 in the next week never owned a pitbike I ride big bikes how do I oil the uni filter like a big bike filter???? they are so open it seems like they will suck dirt so fast!
In order for an airbox to work correctly you will need to have any walls surrounding the air filter at lease an inch away from the filter surface other wise it will impead flow.
While your design is great with effort, the added intake length will change the way your bike will run. It will result in maybe a little more bottom end torque but your high end revs will be hurt.
In order for the pipe not to affect the intake track length, yes it has to grow roughly 30 percent for every inch of length.