GS750 engine swap questions

[Guest]

Hey guys, sorry if this is a questions y'all have seen before (go ahead and let me know if it is, a point in the right direction for research would be much appreciated ). But anyhow, I have a 1982 GS750 and I am reaching a point with it where I am beginning to look at different engines. I have been thinking about maybe air cooled GSXR engines or I have seen that people are a fan of the Bandit 1200 engine around here.

Here is what I want to get out of an engine swap:
1) MORE POWAHHHH!!! I'd like to be at atleast 90-100 hp
2) An engine with slimmer cases. This is a custom bike and I like the way it looks, I would say my first real build so I am sentimentally attached. I love the way the bike looks with the exception of the cases on either side of the block hanging out so far.
3) Better highway gearing. The stock engine is at about 60-70% of maximum RPM when I cruise at highway speed and the high revs rattle you to death.
4) Possibly some weight reduction? Don't know how much there is to be had, but if a decade newer engine might weigh less, I'm all for it!!

Fabrication and spending a few extra bucks here and there doesn't bother me although the easiest/cheapest option is favored. Let me know if you guys have any suggestions!

Thanks for reading/offering insight!!

-Len

[Jedz123]

Best bet? Just buy a new bike.

The 750 frame will flex with a lump that puts out more power then the 750. I've done a 7-11 swap and sure it was fun but it was unstable and dangerous. The forks are inferior, the brakes are inferior, the frame is not designed to take the extra torque. Your not going to get any narrower with an 1157 Bandit 1200 engine. Not much lighter either...

Easy cheapest option? Buy a Bandit 1200. Or if you insist on having a bigger engine swap in a GS1100 engine, same ignition system and coils. Anything else will be costly and IMO not worth the time, money and effort.

If you want a quicker, lighter, narrower bike... It's probably time to upgrade to a newer more modern motorcycle.

[Jedz123]

Oh also if it's a 16V 750 you would want to go the the 1100 or 1150 route. If you have an 8V 750 the only available engine that will fit with out drastic modification is an 8V 1000 engine...

[stevef.]

Thanks for the input. But in this instance I have experience owning and riding more than just this motorcycle. I already have more nimble, powerful bikes than this one so selling it for another more modern bike is not my prerogative. I'm not trying to rip around everywhere and take it racing, I have a dedicated track bike for that. Like I said, this is the first of my project bikes and I'd like to take it another step because I'm proud of what it is so far, I'm getting the itch to do something else to it, and I don't see any benefit or reason to sell it. Also, as stated in my original post, I don't want crazy power, seriously 90-100 is plenty. But, if The larger displacement engines do weigh quite a bit more, what about a GSXR-750 air cooled engine? Has enyone seen that swapped into a GS before? I'm just trying to get an idea here other than "Go buy something that's already newer and better".

Thanks again!
-Len

[Buffalo Bill]

Yes folks have swapped the 1st generation GSXR engine, or the GSXF Katana engine > same thing.
BTW: It's oil cooled, there never was an air cooled GSXR engine.
Just this spring a guy posted his GSXF600 swap into I dunno 550 or 750 frame.
Do a search for such, it's been done many times here, and the other way too > a GS engine into a GSXR frame, as a Yoshimura GS1000 racer replica.

[tkent02]

I'm a big fan of the 16 valve GS1100 engine in that frame.

[Buffalo Bill]

Yeah, great low to mid torque, for the GSXR they swapped high end HP for low end torque.

[Spyder]

I am also a big fan of the 16 valve 1100 engine in the 750. I have NO issues of "instability" or "Frame flexing". It is very right and tight, and has LOADS of torque and great on the highway at high speeds. I would do it all over again, and probably will do it again...

[Buffalo Bill]

I am also a big fan of the 16 valve 1100 engine in the 750. I have NO issues of "instability" or "Frame flexing". It is very right and tight, and has LOADS of torque and great on the highway at high speeds. I would do it all over again, and probably will do it again...

So post a pic for us…

[Spyder]

[Buffalo Bill]

Looks good!
Wow, first look I thought that was a Yamaha 750 Seca.
I read that the 16v 750 was actually a sleeved down 1100, so it must be a direct bolt in swap.

[stevef.]

Thanks guys, that's what I was hoping to hear! I'll do more searching around for information regarding swapping an oil cooled Gsxr 750 engine. I think that might provide what I'm looking for. And that bike is a stunner! Great work! You can't even tell that it's a swap!

-Len

[Crankthat]

I was sent this link from one of our Australian members earlier this year.
A great build.
CustomFighters.com Streetfighter Motorcycle Forum > 370steve- GS750- "timeslip" **** BUILD THREAD ****

[Jedz123]

Looks good!
Wow, first look I thought that was a Yamaha 750 Seca.
I read that the 16v 750 was actually a sleeved down 1100, so it must be a direct bolt in swap.

All but 1 mount... Easy to fab up... They are very similar but have component differences, Clutch assembly is different, oil pump gears (better in the 750), 1 Engine mount is different.

Might have experienced flex for it was an L frame???? I felt the bike shift every time she came up into a wheelie.... Which was often...

[Buffalo Bill]

You did very good work on that bike!
I dunno about the Ls, look at that front fork, they never meant to them to be high performance, kind of another Peter Fonda influenced bike, for EZ riders only.