Cylinder swap for 78gs750????

[fcchavez]

My question is this: I own a 78 gs 750 had it for about three years now and i want to do some upgrades to it performance wise. I was told that the 800 cylinders will fit on the 750 bottom end the other thing i want to do is go to a four valve head and lastly i want to put cv carbs on it for better streetability? I'm not to familar with the gs brand or any of these sport bike models. Any help will greatly be appreciated as i love this bike and want to keep it going. Plus is there anything i should lookout for as far as problems with this engine/drivetrain? thanks again:-D

[katman]

I believe you can swap a 2 valve 1000 block and pistons onto your 750.

[humhead]

a 2valve 1000 block is too big. Others have used an 850 block. I got lucky & found a low priced 1000 (Actually two of them). All the fun & no down time!


Terry

[TheCafeKid]

Damn..lol i just wasted like a half an hour looking thru ebay for 1000 2v heads...anyone got a 750 2v they wanna part with??

[tkent02]

850 cylinders fit on 750 cases, and the later 850 heads are made for CV carbs. They are two valve motors, four valve heads will not go on two valve motors.
My 850 conversion will be in the works soon, will let you know how it turns out. Apparently you have to open up the upper case a tad to fit the 850 cylinder into it, I haven't gotten that far yet.

[fcchavez]

where can i find other engine parts like bearings, seals, stuff like that so i can rebuild it?? thanks so much

[katman]

I thought that was to good to be true. I was talking to a Suzuki dealer dude who had told me that. NOt being familiar with the 70's suzi's I had to take him at his word.

[hotbox05]

850 cylinders fit on 750 cases, and the later 850 heads are made for CV carbs. They are two valve motors, four valve heads will not go on two valve motors.
My 850 conversion will be in the works soon, will let you know how it turns out. Apparently you have to open up the upper case a tad to fit the 850 cylinder into it, I haven't gotten that far yet.

just like a lot of the piston and cylinder kits for vw's .

[tone]

This is only from memory so check it out before getting too involved in rebuilding the engine

early model 850 heads & barrels are a direct swap onto a 78 750 (i've done it) but theres something in my tiny mind that tells me theres a problem doing it with later models, this could be to do with having to open out the cases but i dont think so, i think theres something else, not 100% sure as its been a while since i tried

a bit vague i know but its worth checking out & may save some time & cash :-D

[humhead]

I have an 850 block & CV carb head I was planning to use on my 750. Before I tore down the working motor, I test fit the 850 block onto a spare set of 750 cases. There was interference.
I was able to grind the cases to make the block fit, but I was nervous about doing this to a case full of crank, rods etc. Others have reported that they had no interference issues.

Terry