5 Speed Transmission for Honda Shadow - Is It Possible??
Well, the VLX600 is a four-speed transmission… so, NOPE. It's a type of "unit construction motor," meaning the transmission is built into the motor and you can't separate them.
If you were to put a 5th gear inside that transmission all you'd really get is a 3rd gear that was split in half, rendering it pretty worthless. You'd need to redesign the whole motor to accept a fifth gear.
TJ gives other advice and alternative options in this video. Take a look!