The sprocket hub and the rear wheel are squeezed together by the wheel spacers so there are no bolts securing the sprocket to the wheel. There is the "cush drive" "teeth" that mesh with the rear wheel "teeth" with the rubber isolator between them that could be worn or broken down causing excessive play.

It's also possible that as you are releasing the clutch, the bike starts moving and you stop releasing the lever. Then as the bike builds speed, you dump the rest of the lever and fully engage the clutch. Then the clutch locks up and gives you the jolt. I've inadvertently done this on occasion and it feels just like what you are describing.

I'd try a slow, steady release of the clutch lever and if it still does it, I'd adjust the clutch, drain the primary and refill with the recommended amount of Formula+ and go from there.

 

My mistake, I have an older one and forgot the newer ones have the rubber insert assy

 

I will take a look at my release technique it could be me I may be dumping a little bit too fast all of these are viable options

 

Did you ever find out what this was?

 

Once the transmission is in gear, it is in gear, no jumping into gear as the bike starts moving. It is common that as the bike begins to move there is a big difference between actual speed and what that engine rpm would cause as a speed when the clutch is fully locked up. As the actual speed approaches the "locked up" speed, the clutch grabs abruptly. Don't know what the previous owner put in the primary but a fluid change will likely smooth that out. I have experienced this with several different primary lubes. Some engine oils were worse than others. The Harley primary lube will probably cure this, though it may take a while to "rinse" the old stuff out of the clutch.

The proper, by the manual clutch adjustment procedure requires a "cold" bike so checking the clutch adjustment while you wait would take several hours just to wait for the bike to cool off. Will you be dropping it off one day and picking it up the next? Did they claim the bike had been freshly serviced when you bought it and did that include the clutch adjustment?

 

Operator error

 

My bike had a similar issue. I just installed a new high output alternator. I have 43k on the bike now so I replaced the compensator and chain adjuster as well. Now it not only charges better but the issue like you have described is now gone. The slack adjuster was worn quite a bit. The compensator looked good but, like I said the problem is gone.