Frame Size?

[purl]

I currently have an '05 Bruin 4x4. I'm finally looking to upgrade to something with a little more power mostly to gain a little speed and power when I have my Tatou 4s tracks on in the winter months. My issue is I really dont want to increase the size of my ATV frame. Any one know how much larger cc from my 350 can I go before the frame size increases.
Cheers

 

[maim]

well the 400 bigbear uses the same bottomend on the motor and the 350 bigbear and my 400 bigbear pro are pretty much the same other than some mounting brakets for bumpers.