600 bottom end with 750 top?

[thebook92]

I have a 600 engine with an unknown top end but good transmission, and a 750 that I'm 99% sure I just lost 2nd gear in while riding today. On a scale of 1 to Forrest Gump, how dumb of an idea is it to swap the 750 top end (jugs, head, rods, pistons, etc.) onto the 600 bottom end? Alternately, what about the 600 gear set onto the 750 engine?

[92xjunker]

Different stroke. Swap the tranny.

[arsenic]

On a scale of 1 to Forrest Gump, that is a 100% Forrest Gump idea. Just swap the transmission, it's the same thing.

[thebook92]

Had a feeling I wouldn't be able to do it, but I figured it might be worth a shot. Trans swap it is. Thanks, guys.

[arsenic]

Had a feeling I wouldn't be able to do it, but I figured it might be worth a shot. Trans swap it is. Thanks, guys.

Oh, you CAN do it. I swapped an overbored 750, actually an 813, on a 600 case and crank shaft. I bought a GSXR 750 long stroke cylinder block, and had it bored. Modified the stock 600 upper crank case to accept the larger cylinder sleeves. Had the OEM GSX600F crank shaft lightened and balanced. Used Crower con rod with the wrist pin reduced from 18mm to 16mm. Etc, etc, etc. Now it is possible to do that. #1, it's expensive as holy hell. #2, it's not anything you should do because you lost second gear. I had the stock transmission under cut also. I did that because I can. It's not a financially responsible thing to do. Also, the 98+ 750 cylinder head is ported and polished. The valves are back cut 40 degrees. After market cams that are degreed. The list goes on. I did that for something to waste time and money on. That was before I found I really like wrist watches. 22 watches later, I haven't thought about that motor I have to finish in a while. You see, the GSX750F motor is a short stroke. The GSX600F is a long stroke. Unless you bought a bunch of random shit, you can't just combine those two. The cylinder block is a different height, and the short stroke crank shaft is thicker, so it won't fit in a 600 crank casr, and the long stroke con rods won't fit on the crank shaft. There's really no way to combine these two engine halves.

[92xjunker]

And we're all still waiting to check it out, completed...

[arsenic]

Just bought this last night

[92xjunker]

Looks like the one I bought

[arsenic]

It has a 50mm lug to lug tip length. The one I sold you had 53mm length. They are both 44mm diameter, but that will wear smaller because the lugs are shorter. Also, that one doesn't have a crown guard. I've grown rather fond of cushion cases though.

[thebook92]

Oh, you CAN do it. I swapped an overbored 750, actually an 813, on a 600 case and crank shaft. I bought a GSXR 750 long stroke cylinder block, and had it bored. Modified the stock 600 upper crank case to accept the larger cylinder sleeves. Had the OEM GSX600F crank shaft lightened and balanced. Used Crower con rod with the wrist pin reduced from 18mm to 16mm. Etc, etc, etc. Now it is possible to do that. #1, it's expensive as holy hell. #2, it's not anything you should do because you lost second gear. I had the stock transmission under cut also. I did that because I can. It's not a financially responsible thing to do. Also, the 98+ 750 cylinder head is ported and polished. The valves are back cut 40 degrees. After market cams that are degreed. The list goes on. I did that for something to waste time and money on. That was before I found I really like wrist watches. 22 watches later, I haven't thought about that motor I have to finish in a while. You see, the GSX750F motor is a short stroke. The GSX600F is a long stroke. Unless you bought a bunch of random shit, you can't just combine those two. The cylinder block is a different height, and the short stroke crank shaft is thicker, so it won't fit in a 600 crank casr, and the long stroke con rods won't fit on the crank shaft. There's really no way to combine these two engine halves.

...and here I was thinking about a port/polish/GSXR cam swap while the motor was apart, and you drop that on me.