I use the NHIS pump gas with no issues. I use VP C12 when I can get it. The C12 seems more tolerant of slightly improper jetting, but like to be in an engine that is run really hard. It only seems to provide any real advantage over other fuels when you are really beating on your engine.
Down side of VP is it produces heavy deposits unless you are running the engine very hard, it's not great to leave sitting around in carbs either.
I don't really go out of my way to get the VP though. If someone has it, I'll buy it, otherwise I'll use what's out there. I don't think my engines make the compression necessary to really REQUIRE race octane fuels.
"it's not great to leave sitting around in carbs either."
I'm glad you mentioned that, I'd completely forgotten that I had to clean up my Carb after letting that stuff stay in there over the winter, even with stabilizer mixed in.
I've been using VP Red for flattrack and Supermotard. Honestly couldn't tell much difference in any of my 4 strokes, made a noticable difference in the YZ125 though! I started using VP instead of AvGas, because I was told I wouldn't get a proper plug reading with AvGas, plus it is readily available at most speed shops.
"I don't think my engines make the compression necessary to really REQUIRE race octane fuels."
Have you asked anyone at VP Tech Support? In general, I've found these people to be very helpful. I've also had good luck talking to the folks at Torco about their oil products.
Good point about the VP. Most of the rave reviews I hear are from 2 stroke racers.
I know the VP C12 is more octane than I need so I really need to switch to something like their new "four stroke" fuel...called something like Ultra4 I think. It's lower octane and specifically designed for four strokes with compression ratios of about 11:1 or less.
The VP website has some good info on their fuels.
The C12 is strange, hard to explain really but at high rpms and during hard running the bike doesn't seem to make any more power it just seems to run more consistantly. Fewer hiccups, smoother power delievery...kind of evens out the peaks and valleys. Although I'm actually probably costing myself a bit of power using anything more than about 104 octane. I think the C12 is something like 110 or 108. It does stay nice and cool in the float bowls though!