Possibly bent subframe

[YFZ450CW]

My white brothers headpipe keeps braking and they think it it a bent subframe but the subframe does not appear to be bent. I have heard it is the subframe flexing and i dont have like 500 to buy an aftermarket subframe what else could it be?

[WORCSYFZ199]

I cracked my subframe in 3 places and broke my stock swingarm, I dont really have the money for aftermarket either but its the only way to go