pivot arm shaft question

I'm a newbie. I am modifying a KZ650, replacing the swing arm with a different one. The original shaft size is #16 in diameter, 306mm long. My new swing arm requires a #14, 306 to 310 mm long. Does anyone know a bike that has that size shaft? I've been having a heck of a time finding it. All the sites I've looked at list the shafts by bike only, not length and diameter.

JUST WONDERING IF A MACHINE SHOP COULD TURN YOUR BOLT DOWN TO 14 AND RE THREAD IT.You would still need to fill the space in the frames bolt hole form the 16mm bolt hole to accept the 14mm bolt.You could have them leave it 16mm near the bolt head then you would only have to shim one end.

good idea. I think I may have to do that. Thanks.