I found this post randomly on ADVrider, proof that someone actually raced MX on a CL350! I'm just pasting the whole shebang, no way I'm finding it again:
"1968 Honda CL-350 Racer
The question was ask if a Honda 350 ever was used for motocross? Well I'm sorry to say that I raced one in the first motocross in N. California I think it was 1970 I got a third behind Brad Lacky and Dick Mann.
Later I converted it to a TT rig.
It had ceriani M/X forks and Koni shocks and the engine was pumped. Those were the days!!"
Dig the captain america paint job in#1
or the groovy Honda in #2
Pretty psychedelic brother....