Given that a belt is wider than a chain, some modification of the engine case and other parts may be needed for clearance. Replacing the sprockets with pulleys might require custom machining to have them attached securely. A belt of the proper length would have to be located.

It would likely cost more than the motorcycle's lifetime of new chains and sprockets to make the conversion. You should consider bang for the buck.

 

Belts are less than an inch wide by 2005 on the VRod . Some was 5/8" wide. My FTRs chain is 7/8" wide,and was worn to the limit 4200 miles.
Old mill chain will get that for a 10 spot . There will be challenges to change but the mess and noise will be gone .

 

In addition to what Dods mentioned there's the difficulty of finding pulleys that will have the same bolt hole pattern as your existing wheel hub and the same splines as your transmission shaft. Almost any combination of size / tooth can be found on pulleys that fit Harleys, but it would take some expensive machining to get them to fit, like he said. It could be done, but I can't see it being worth it.

Have you tried an O-ring chain?

 

The right direction - make sure the sprockets are still in near perfect shape, then bite the bullet and buy a new good O-ring chain and put it on. I would verify the near perfect fit of the old sprockets to the chain before I installed it.

A new countershaft sprocket isn't too expensive usually under $35. The rear is more expensive but usually doesn't wear quite as quick.

The perfect tooth profile is a perfect round U shape. If the U shape is even slightly enlongated the sprocket will wear a new chain faster due to the fact that the teeth won't be seating and pulling evenly over a maximum possible links.

Fact is if it was me I'd do the whole thing since it would be starting from new and you would likely get well over 20,000 miles with minimal wear.

Once the pin areas have been contaminated it will be hard to expect that old chain to ever work right again. My bet is the previous owner(s) pressure washed the bike and blew that nice soapy water in the links and ruined the chain.

Honda only used a belt on the 83 CM250 and I doubt it would be right for the 450. You would also pay through the nose for the pulleys. They are a whole lot more expensive than sprockets.

 

Before you commit to an O-ring chain, check the clearances around the front sprocket, since they take a bit more room. I can't use one on my CB450K3, without modifying the clutch mechanism, because of the clearance issues.

 

The bike still has the original 'O' ring chain on it.

Last summer, when I had the chain off and cleaned, I checked the 'O' rings. they were all there and still pliable.

Both sprockets look perfect, not just to my eye, but three others who work on motorcycles for a living.
One guy has been at it for nearly forty years.

As I said, I'm not beyond modifying or fabricating something to make it work.
I would think that with all the belt-driven bikes that have been made over the years that there's something that could be modified to work. It's just a matter of getting the correct ratio and belt length.

I'm going to talk to a guy today who has a bunch of parts/part bikes. He also has the knowledge.

 

If you are dedicated to it, see if you can mount up a Kawasaki 440 LTD wheel with the belt drive pulley after you see if you can fit the front pulley. That is likely the best shot at doing it.

You're going to have to align the pulleys once the front is done, possibly modify the swing arm for room. It isn't as easy as it appears.

Like I said, before I blew all that money (belts ain't cheap) I'd put on a new O-ring chain, a good one, and run it. Then you will know if it is that the O-ring chains aren't that hot or if the original owner(s) did what I said, hosed down the chain with a pressure washer or a good strong spray from a garden hose and ruined the chain. If it goes the way I'm guessing you will get good life out of a new chain and save a lot of money and headaches in the long run. But good luck to you if you try the belt.