We have a fairly huge beetle (3-4 inches) here in Arizona called the Palo Verde bug – it is a long horned beetle (named because their antennas are long) and by all standards a good size bug. I can only imagine getting hit by one while riding your motorcycle. It would probably knock you pretty hard, maybe hurting your head or at the very least disorienting you and knocking you off the bike.
The larva are cream colored , typically with a brown head, and feed on the roots of trees, which causes branch dieback. In the wild the most commonly affected tree is the palo verde and just after monsoon the mature insects exit and look for mates. These adults don’t eat and essentially are only interested in mating.
So if you see one, don’t panic and be aware that within a few weeks the adults will die and come out once again during the next monsoon.