The performance gain was huge with the Keihins. The tuneability was much better than the stock carbs. I have a really freeflowing intake system that I could not jet for with the stock carbs.

I'd be happy to try to help you out with your jetting but my feeling is that the stock carbs just won't be able to handle it.

I recommend the keihins but maybe the Edelbrocks would be just as good for you.

When and where are you riding now. If you wanted to meet up sometime lets set it up.

Whatever happened to the Phoenix Dyno Day?

Where did you get the keihins? Were they a kit specifically for the Raptor? How much $$$? Are they a direct fit for the stock air box and intake boots? What venturi size are they? Let me know, just curious. Also, when are the edelbrock kits coming out?

The Keihins are a kit from Carb Parts Warehouse. They are not specifically for the Raptor but fit rather well. I only had to do some small amount of modifications.

1) Seperate the frame rails under the gas tank by using fender washers between the frame and the top engine mount.
2) Put a little ding in the exhaust pipe to clear the carburetor accelerator pump.
3) Space up the rear of the gas tank.

The bolt to the stock airbox and fit up to the intake boots(not perfect size and spacing but no problems at all).

I think I paid about $750.00 in all and it is well worth it. I would recommend doing this mod even before any type of exhaust. I did really well against every bike at Oldsmobile hill in Glamis. I want to dyno it but haven't had time.

They are 35mm's but if I had my choice I think I would have choose a smaller size like 30mm.

I have no idea about the Quicksilvers.

I had this problem with my snowmobile once, the needle and seat where the gas flows into the carb had a small seed in it.It would run fine for a few minutes or until I went fast.The gas flow could not keep up to the demand.After stopping for a few minutes the carb would fill with gas slowly and would run good again.Just something to check.