My 1995 has less than 60,000 on it. Carbs have never been off, the emission plugs are still in the housings and the original petcock is still on the bike. No fuel filter has been added to the line, depending completely on the strainer screens in the tank. It starts and idles, even after winter storage. The bike has gotten a couple ounces of Marvel Mystery oil almost every fill up since it had 1500 miles on it. My 1997 had carb, petcock, and tank rust problems when I got it that I never got sorted out completely, the 1st owner never used marvel, but he loved screwing with the cabs and though he could solve everything with fuel system cleaner. The original owner never used Marvel oil. One of the 2004's needed the carbs pulled and cleaned at the 600 miles, after setting several months in the showroom with some gas in it. The fuel line also got flakes from inside. I think the alcohol in the gas is murder in the whole fuel system, and the Marvel oil counter acts the corrosion, rust and rubber rot.
I know I just jinked myself, my 1995 bike will probably hydrolock and burst into flames tomorrow.