I sold that stuff years ago, I wouldn't use it, your parts guy is just trying to get an add on sale.
A newer bike using Amsoil has no need for a crankcase solvent.
That is a product that was developed back in the days of non detergent or low detergent motor oils and the crankcases would get pretty nasty between oil changes.

 

Good idea if you have open pipes and there are a lot of mice around.

I know I'm off topic in a H-D forum but there's about 2 feet fo snow outside and I'm bored so I'll tell ya a story.

Years ago I owned a 66 Chevy with a SB 283. The car was hit and run making it unworthy for the street so I stripped the body off. The only thing left besides the power train was the motor, dash, front seat and a can for fuel. The mufflers were also cut off - straight pipes only. The car (?) was a blast to drive because of the power to weight ratio. One spring I tried to fire it up but was having trouble. When I checked the plugs I found a mouse nest in a couple of cylinders. Yes, a mouse can get by the valves into the cylinders and the lack of muffler made it easy for them to get in. See, it's sorta on topic... I changed the plugs, gave it a shot of gas and fired it up. Mouse spray paint ain't pretty.

BTW, the old Chevy ran for a couple more years before a farmer bought the motor for his grain trick.

 

I tried to upload a picture but for some reason was unsuccessful. Gunk Flush is crank case cleaner.

Jag, thanks for the info.

 

I store use sta-bil then ride "Moth ball's he he" Gotta tell this one. Next door neighbor was kinda old went out in his back yard stepped on a snake. Scared the chit out of him. I told him to put a few moth ***** in his yard and the snakes would leave. Next day I looked out my window, low and behold it looked like it had snowed. bet there was an inch of moth ***** covering the ground around his back door.