Did I read on a post (maybe on a different forum?) that you were going from 40mm Keihins to 42mm Keihins on your STXR? If I'm remembering this correctly why that particular route versus something like a 44mm Mikuni? I'm just wondering because I just switched from a very similar stock carb to the 44mm Mikuni on my Polaris and have seen some impressive gains, especially with the new-found ability to easily adjust my carbs...just curious mostly. I know I didn't want to go more than about 10% biggter and risk seriously impacting my fuel cunsumption.

You are correct, I am going to 42mm Keihins and my main concern is fuel consumption. The reason for going to AM carbs was mod based. The stock CV Keihins are not very mod friendly after a certain point because of the lack of adjusters and the CV slides.

Since I dont (currently ) want pipes, but still want more accel/speed and reliability, Crone recommended that I go to AM carbs to get away from probs resulting from too many mods with the CV probs. He said Novi, I said NoWay So I found a set of used 42mm Kehins. That way, more mod safe, no slides, can be tuned and the minimum amount of fuel range loss while getting a lot more bottom end and a little top. And being able to keep prgressing with mods if I want.

I think we will probably be installing them when the water temps come up a bit. I will post some results on the Ultra150.com forum when I get some.
If I end up getting the SC and its really good on fuel consumption, I might bite the bullet and put triples on the STXR. I just hear that's just too incredible to feel.

I wish my SLX would respond well to triples...

I was just curious because if I'm not mistaken the Polaris skis run almost the same carbs stock and I've just recently swapped over to some 44mm Mikuni's on my SLX. I got everything from the manifolds up at a really good price (about 1/3 of what NOVI wants) and so far have seen some impressive gains. I ran into the same thing as you; the stock carbs just become mod-unfriendly at a certain point and fuel consupmtion was also a priority of mine.

I just thought you might have known something special about the Keihins...

BTW I've seen almost 2mph on top and big acceleration gains on my Polaris...hopefully you'll get similar gains in your route...

Well, the Keihins fit on the stock manifold after opening it up slightly. James is extremely familiar with this setup and has worked with it for years. So it was probably the least expensive way to go for me, not to mention it will be the least impactful on the mileage.

Nice gains on your setup, I don't think I will see as much, but I am really looking forward to more accel.

I was really suprised by the top end gains. Mostly I was anticipating accel gains also. I think the biggest gains came from finally being able to fine tune the mix.