I have an actual Mugen Ninja motor. It's an original BO1 not BO1A. It's in better shape then that. I never could get a tune I was happy with and the piston and button look better then yours.
Pay me the shipping charge to you and I'll give it to ya. Can't hurt and maybe you can frankenstein something that will run. Should be more then 6 or 7 dollars USPS.
Write this lesson off as NEVER buy a used motor from the internet. From somebody at your local track who you know and trust there tuning maybe, but NEVER on the internet.
PM me if your interested in mine. it's collecting dust.