I've yet to visit either, but as you may well know MANY motorcycles are built for global export in Thailand, as well as for the obvious domestic market. If it's of interest to you, I'd see if Honda, Ducati, Triumph, Harley-Davidson, etc have anything worth seeing at their factories even if they don't offer tours of the facility. I know that Thai Honda at least have a small museum at one of their factories. Beyond that I'd recommend checking out a "Cub House". They are the lifestyle oriented motorcycle dealers for Honda, similar to some Harley-Davidson dealerships in the US, but for the small bore bikes that the world, and Thailand, run on.