[bsbiker]

I have a new to me 06 440. At first it was running rich and had 220 mains. I went to 200 mains and now it will only go 40 mph! Any clues on needle position?

 

[flatlander_summit]

Dude, it's a cat, that's all you will be getting out of it.

I don't know if you're running the sled in race trim or trail trim, but I ran 320 mains in my rev 440, I think you sound like you're probably running lean and have a belt/clutching problem.

 

[Quinlan]

Presuming you are talking about the 06 440 SnoPro...it sounds like you are pretty lean running those jets. From all the research I've done, this is what I've concluded...

Race heads - 110 octane
260-280 mains
timing +1 to +3

Trail heads - 91 octane
around 310 mains
stock pilot
stock needle, middle clip
timing -3