01 CR250 swing arm bolt not fitting through 500 engine cases

[BIGGUNCR500]

I'm sure this has been dealt with before, but I did not find the thread, so I'll take the verbal battery to get the answer I need. Here is my situation -
I was getting ready to install my 500 engine in my 01 CR250 frame when I found that the swing arm pivot bolt was too big to fit through the engine cases. When I bought the roller, I was told it was a straight install. I am not a machinist or mechanic by any stretch of the imagination, and since this guy has a business modding these frames, I took his statement at face value and assumed that he would advise me if I needed to do something like this. I should have known better.
And now, my question: since the bolt does not fit, should I take the motor to a machine shop and have the cases bored out or is there another alternative that I am missing?

[Roostius_Maximus]

if you have 1988 or older engine cases the rear bushing is smaller. You'll need to machine them. Some guys use old 250 case bushings and drill the aluminum of the case to accept them. Others drill the bushing.
I've replaced the bushings with newer model ones.

[freeride588]

if you have 1988 or older engine cases the rear bushing is smaller. You'll need to machine them. Some guys use old 250 case bushings and drill the aluminum of the case to accept them. Others drill the bushing.
I've replaced the bushings with newer model ones.

Yuppers

[scooter5002]

Don't suppose you bought it from some douchebag named George Fanelli out of Toledo, did you?

[BIGGUNCR500]

Yeah, that's him. This bike has been a full on pain in the ass - one thing after the other has went wrong - wrong shock linkage -I had to replace it, fork tubes were pinched at the bottom and I couldn't change out the springs w/o spending way too much $, etc.... I just hope that after this it goes together. Really regretting this whole deal.
As far as what to do, I think I understand, I'll see who I can contact in my area to remedy this and keep you guys posted on how it goes.
Thanx for the help.

[scooter5002]

I went through it with that prick too. He'll never get any smarter, and his work will never improve. He's just a fuckin' hack. Short of posting a billboard on his street with a notice telling the world what a douche he is, I don't know how to stop him from fucking the masses. He needs to be stopped. Just a thief.