Don't know, but after about 40 grand I still haven't had to adjust the shims.
see it's comments like this that have me a bit worried. over on the volusia forum where i'm very active, there are people who make the same remarks regarding valve adjustments.
but here's what you have to think about...............
as you ride down the road, slowly accumulating mile after mile, your bike is continuously wearing out. but since it's wearing, as you are riding it, you don't feel the difference in performance, because it's not a ON-OFF difference.
think of it like going from riding your bike, to trying out somebody elses bike of the same kind. they feel different in power.
when i did the valve adjustment and carb balancing on my wifes ninja and my volusia, the bikes were COMPLETELY different beasts afterwards.
it made improvements in idle, vibrations, how much choke was required, how sensitive i could adjust the choke, and how long choke was required.
it's one thing to go over on mileage for valve adjustments by a little bit. but when i hear people say they have 20, 30, 40, 50,000+ without adjustments, that worries me, because not only are you missing out on the fun of a well performing bike, but you are also causing excessive wear and damage to the engine.
I guess i'll try to research the mechanics of the vulcan engine some more to find out how they are different from my suzuki and ninja engine, and then perhaps i'll just go with my own service schedule. I just think i'd feel better making sure that everything in the engine is properly within spec, and that i'm actually getting all of my available power, and not wasting it on a poorly tuned motor.