You are right that when the Avons are truly round and true they are good tires for the most part. I've had cupping problems from time to time with Metzler, Avon and Michelin on the Bosses. I suggest that almost any tire can be problematic as a result of the weight and braking dynamic of the Boss. My real sour note is a result of the very high percentage of out of round tires suggesting that Avon's attention to quality control is lacking and that unto itself is worrysome. I've often cranked the Boss, V8Chopper and FJR up past the 140 mark (160 on the bigblock) and all you think about is tire failure. I just can't bring myself to trust Avon.
The Jap bike guys who are running the Busa's, Ninja's and FJR's for the most part have also nixed the Avons. I know Yamaha was using them for original eqpt on the FJR's but very few went with them again at replacement time.
Tires, like carbs, fuel brand, oils, etc is highly subjective and for some reason many folks develop brand loyality. I have no brand loyality when it comes to tires. Currently using Metzlers on 3 bikes but that could change next go round. The only thing I'm sure of, Avon won't be one of my choices as a result of the quality control issue. Best regards,