85 250r frame strength with a big bore motor

[250rmanfmf]

Hi Guys, I have a issue and want some insight. I have a 85 250r with a bent sub frame. I am in the process of building a 431cc puma motor. I am wondering what areas of the frame become weak with a larger more HP motor? I am either going to fix my bent sub frame or if the frame becomes weaker with the big bore then I was looking into a Chromley frame. I really dont want to spend the $$$ on a Chromley frame but if it will save me a broken frame down the road then its worth it.

Again any info would be great. Its causing maddness trying to figure out what I should do.

Thanks
Tyler

[zmpolaristech]

I have seen at least 3 250r's broken in half at the front down tub.... they split just above the lower rad mounts... If anything, I would plate that area prior to building a 60 horse ATCR...