Unless of course they ask you the engine size and you lie on the application. Then all bets are off.The insurance co. cannot legally charge you more for insurance on any vehicle that has been modified unless you take out a policy that covers specificaly the modifications made, called an addendum policy. If the VIN says that it's a monster 620, then the insurance will be for a monster 620, regardless of what motor is in it. I know a guy who has a 996 that is titled (legally) as a 750ss. He had a totaled 750ss and wanted to put the motor in a 748 frame he found on Ebay with no title. He had the vehicle properly inspected by the state before and after the swap, and legally had the state scratch outthe 748 VIN and put his old VIN in it's place. Then he put the 996 motor in, Insurance is for a 750ss based on the VIN.
This is what I figured. The engine oil is supplied to the wet clutch assembly and I do not think there is a feasible way to change it. A different engine or bike IMO is the way to go.I think this topic has come up before.
The big issue is sealing the clutch so the oil stays in the engine! While it may not be necessary to change the bottom end out, it is very likely necessary to crack the case so that the proper seals can be installed. This could also likely involve some machine work.
I'd be surprised if it were that easy to make the swap. conventional wisdom has it that the smaller bikes have wet clutches because they are less expensive to manufacture (keeping them at lower price points) than wet clutches. The difference in cost is said to be in the sealing. Soooo, if it makes that much difference in production, a retrofit job will be even tougher.