400 exhaust on a 750 csr

Is this something that will work?

It seems to me that it wouldn't.

It would be REALLY restrictive wouldnt it?, and you would probly have to bend the pipes to fit too right?

That's what I thought.

Some guy is trying to get some off of me and he says that some people online told him that it would work.

I'm 99% positive that it won't work stock and don't want to rip him off by having him take something that won't work.

Why are people so adamantly difficult?

measure the inner diameter of the 400 pipes vs the 750 pipes, the difference should convince him, but if he still wants to try it, you did your best to try to tell him otherwise
if he did manage to put the smaller pipes on, he would probly have to rejet smaller and would have a loss of power