I imagine that the issue with the 103/110 at sustained speed is heat build-up causing ping and the knock sensors are retarding the timing to counter it.
That's the 2 valve head with higher compression tax! Our cylinder heads charge cool with the air/fuel mixture going into the cylinder absorbing heat from the previous cycle much better due to the 4 valve arrangement, and a reasonable compression ratio works with this. One reason I would never go for HC
pistons in a Road Star. Like I've said before, Yamaha spent a lot of money developing this engine for reliability and durability. I'm not opposed to feeding it more of what it wants, as a richer mixture helps to cool the internals, but when it comes time to fire, you only want that happening on schedule!