I think this would help quite a bit as the tops are pretty sloppy if you look inside them. Cleaning the flow is always a benefit, as is slightly larger valves. But wait till you see how much this will be! If you do it, you MUST replace the valve seals (not the guides themselves) as they are designed to be replaced if you remove the valves. Like most seals, once you take it off, you throw it away and replace it. I know the Triumph valves are in the neighborhood of $50 EACH and ther are 8 of them, seals are about $7 each too.
If you go with larger diameter valve stems, you will need to have the shop make new valve guides since they are not available as seperate parts, they are part of the entire head assembly.
