It's sort of my job, lol. Username checks out, I guess.
I've never rebuilt a Pioneer 500 engine, but I've got several dozen Goldwing engines, other Pioneer engines, dirtbikes, atvs, and watercraft engines to my name.
I figure we'd charge 12 to 15 hours labor, parts would be approx. $1000 or so depending on cylinder/head condition (that includes a crankshaft). So around $3k or so. But don't quote me on that, heavily dependent on parts.
We're in Cincinnati, OH.