Potential Big Bore Performance kit for GS550

[Neveragain55]

Worth a read
https://magazine.cycleworld.com/arti.../suzuki-gs65og

Excellent article, thanks...

[rphillips]

You said a 1980 GS550, that's 48 HP, going to "83" GS650 eng. that's 73 HP will be a 25 HP increase, that's a roughly 50% bolt in increase, and the reliability of a stock OEM eng. "if it will bolt in". Thinking building your 550 48 HP to 73 HP would be a pretty big ordeal.

[salty_monk]

If it's lightweight you're after my guess is that the 700 or 750 later engine is probably lighter or similar in weight to the 8v engines.... It's also a lot more "racy" to ride as it's 16v. The 700 is 80hp, the 750 from 1983 is 83hp the 650E is 73hp (it's actually 673cc).

One thing I don't know if you've thought of.... the 550E is a 6 speed. The rest of them are all 5 speed.

[Neveragain55]

I have made a final decision (which will please many in here because it was the majority consensus to do this)

After reading all the replies, burning my eyes out on cafe racer sights, researching everything there is to know about the GS range of engines from the 450 all the way up to the 850, and after talking with my suzuki guru buddy who spent most of his life building suzuki race engines.........I've decided on doing the 650E cylinder section graph onto the 550.

We've come up with a plan to wring as much horsepower as possible out of that setup and even play around with the gearing to get the most we can out of the close ratio 6 speed that comes with the 550.

The best part of course is that we keep the weight down and the bike will be a "sleeper".

750 up to 850cc riders will be embarrassed when I come whizzing past them (even if only for a little bit) surprised at how fast my little 550 scoots.

I'm super stoked about it and I've already found donor parts for the graph.

Everybody that replied gave me a lot to think about and a lot of insight, and it was all very helpful.

I promise to come back in at some point and start a project thread complete with pictures.

For those of you that may have seen some of my other posts you'll know that I started a Frankenstein build a few years back by putting a punched out to 1200cc 1989 GSXR1100 Slingshot motor into a 1979 750 frame.

I put cool "piggy back" style shocks on the rear keeping the dual external shock setup that the bike came with because I'm really not a fan of the single shock in the center mod that so many people do.

To the folks that do that, please don't shred me just because I mentioned it. (to each his or her own)

She's got upside down forks from a 1996 GSXR750, and a (wide enough to fit 180 rear tire) aluminum, rear swing arm that came from England. (I have no idea what brand)

That bike got put on hold for quite some time but we're starting back up with her soon, and I'll post updates of her as well.

Thanks everybody........