Will '79 GS 1000 cylinders and pistons fit on a '78 750???

[tkent02]

What is the bore and stroke of a 1000?
Will this work with a little persuasion or is an 850 top end the best I can do?
Anyone with personal experience with this?
Thanks,
Tom
tkent02@gmail.com

[Ghostgs1]

The GS1000 bore is 70mm x a stroke of 64.8mm. I have no idea if this is a possible swap. Ray

[BadBillyB]

No..it is not possible. Just put a 1000 motor in it.....Billy

[humhead]

I've never heard of anyone attempting this particular swap. I do own a 79 750 & 3 78 1000s, so I can tell you that there are a lot of potential problems.
1. Cutting the cases to allow the 1000 block to fit. (This is a definite must do.)
Expensive machining & full teardown of engine required.
2. There's a 8.4 mm difference in stroke. How did Suzuki compensate for this?
Connecting rod length, piston pin to crown height & block deck height may be different.
3. Combustion chamber size difference. Using the 750 head is asking for trouble.
The combustion chamber diameter & volume is significantly smaller than the 1000 bore. Piston to valve contact & or piston to head contact is a probable issue.
The 1000 head will solve those problems, but the compression ratio will be ridiculously low. This means milling the head/block to raise compression. This means more potential piston to valve clearance problems.
4. Any change in deck height means you'll have to adjust the cam timing. You'll need adjustable cam sprockets & a degree wheel.

I hope by now you realize that this isn't a good idea!


Terry

[nastyjones]

My advice is to use 850 parts. I'm putting together my 78-750 2-v using 850 cylinders, head & pistons. All it took was a little grinding on the cases with my Dremel to get the 850 stuff to work. So this is really an easy swap.
What I do need to know is how much to mill off the stock head & block for a increase in compression. The 850 head will allow me to use modern cv carbs, I have a bump in displacement & (hopefully) a good boost in power as well when accompanied with a header & rejetting.

Paul