You certainly can, but you run the risk of stalling the bike unless you are able to simultaneously pull in the clutch lever...But for simply scrubbing off some speed, sure.
Maybe you'll need right foot clutch then

You certainly can, but you run the risk of stalling the bike unless you are able to simultaneously pull in the clutch lever...But for simply scrubbing off some speed, sure.
So, why couldn't you run the LHRB without a auto-clutch?
I've been a mechanic for 25 years my hands and wrists hurt when riding my 500's with a stock clutch set up(all have been converted to hydraulic). I race my GG and after installing the rekluse my hands/wrists don't hurt and I'm much much faster in the really tight single track. It's like cheating to me, but at my age(44) I need all the help I can get.I had a severe dirtbike accident over 20 years ago where I shattered both wrists. My left wrist had surgery with pins and an errector set attached to the outside. My right they casted for 8 weeks.
At 42, I'm beginning to get some painful arthritis when I ride. I'm thinking Flexx bars or Rekluse to ease that and make life easier.