I've tried making one myself and I'm half impressed with it (attached for you to try out).

I was wondering if anyone has made or can make some sounds for LX4 which sound similar to a motorbike.

Hayabusa would be the best example for sound I guess, being the most common bike engine swap in 7's and being the closest to what is in the LX4 (minus 10-15bhp).

Anything you can come up with will be most appreciated.