Hey guys, i just built my Ultimate 8043, it is really cool.
but there is a small problem that the left and right side drives in different speed so it cannot just go straight .( i noticed that some guys also complain about this issue)
i think it is because of the gearing design is different between 2 side, the right side gears are way complex than the left side, so my solution is replace the right side motor from M motor to L motor .
after i made this change, it works perfectly fine, hope this small tips can solve your problem.
Also i have extend the length of the boom so it can help to go through some blocks.