Yeah, that's a bit too hot.
On my truck I have an electric radiator fan ducted to the motor endbell that blows air through it continually. Helps a lot! Not sure what kind of fan you could use for a motor that size, though.
And just for kicks, how about water cooling? Wrap some copper pipe around the motor, and circulate water through a radiator. Ya never know.
Awesome machine, BTW. Just out of curiosity, did those contactors come out of a forklift? I have a few just like that from a lift...