Engine shaft question... HELP!

[MNTravis]

I need some advice here!! I got my brand new Honda GX670 for my custom cart the other day and finally got around to messing with it. UNFORTUNATELY when I put the clutch on and sat the engine up on the frame of the kart it became quickly evident that the driven and drive clutches were way off from lining up with each other. What it comes down to is the fact that the shaft on the Honda is 3.5" long and with the way the inner shaft of the Comet clutch driver clutch is built, it only takes in 1 9/16" of the shaft before it bottoms out and will not go in any further. So then the clutch sticks way out and there is no way I could line up the two clutches even with the engine pushed all the way to the right as far as it can go without interfering with the suspension/rear wheel. See the pictures attched.

The immediate option that came to mind was that if I simply cut off 1 3/8" of the shaft, the clutch would then fit on correcty and allow the two clutches to then line up. There would be 3/4" of internal thread remaining on the inside of the engine's shaft and there would be exactly the right length of key left on the shaft for the clutch. Just makes me nervous to start hacking up a factory new engine, but there doesn't seem to be any other choice if I ever want to be able to use the engine for this kart! I assume I could use my portable metal cutting bandsaw (or even a hacksaw if I had to), although the shaft is 1 1/8" thick of hardened steel, the inside is drilled out to 7/16" so it would probably no be too bad of a job to cut it off??

Have you ever cut one of these things off or know if there are any possible problems in doing such?? I am looking for any advice I can get before I make an irreversible move!! What do you think? ANY ADVICE IS APPRECIATED!