Welcome aboard! Sounds like you're well into this machine already. One common issue if it dies for no reason when running is the gas cap is clogged and not venting. Try running it with the cap off once you get it put back together. To find the exact part numbers you need for that machine, including every nut and bolt, go to servicehonda.com and search for OEM
parts/ATV. This will give you the exact part numbers (with US pricing) and will tell you if it's available or not at the dealer. Someone on here might have an exhaust, just be patient. Royal Distributing out of Ontario (I know, I know On-terrible!) has a lot of items for ATC's too maybe even an aftermarket exhaust. Did you order a repair manual? Did you mean "Repair Manual" or "Owners Manual"?