Alrightly, I know there are 555cc kits lurking, but I've heard tell of 632cc kits.

What I want to know is where we find these parts. And how much my checkbook will have to bleed first.

Also with that kind of displacement I'm sure head work will be needed, but what should I do? How insanely difficult is the GSXR750 head chop?

Cams: Don't even know where to get them, let alone what this motor would want

Carbs: Can the stockers feed 632 hungry CC's? Or even 555? (Obviously a rejet will be needed at least)


I'm going to have my bike stored inside this winter and lots of time to be working on it. I'm planning on the bare minimum of: Carb Tear Down and re-jet, Exhaust system, K&N lunchbox, New rear shock (RGV250 or better) and of course the stuff that's gotten worn out (brake pads and tires) I'll probably do a cam at the same time.

Given the chance though I'm going to knock the cylinders out to 555, or even 632. Prefferably with 10.5 or 11 to 1.

Yes there is rather cheap conversion kit for the gs to convert it to 645cc. Also gives about 70 HP and a lot more down torque.

The kit is called SV 650. If you sell your GS and add a bit more $$$ you can have it . But this kit is too easy to install. If you want to wrench more, then make your GS a frankenstein.

Cedric Smith actually had them to 680CC at one time. He was breaking cranks in shortie 12 lap races. Then he went to 569 and was down on power and later to a 580 complete with ferrari F1 pistons and he had the power and didn't break anything.
Cool.
Srinath.

I was wondering if it would be possible to swap a bandit 1200 center two cylinders, and 4 valve head onto the bike. I have no idea on the sizes and demensions or if it would work, but it could keep you busy for the winter  but seriously, if you can find some pistons that have the same size wrist pin, then you could sleeve the cylinders and bore them out just about as far as you want. If the weight is more than a couple grams off, you'll need to pull the crank and have it re ballanced.

As for the heads and cam I don't know. A 4 valve head would definatly help take advantage of the displacement, but you may be able to fit larger valves and port the heads to get some more flow.

If you go from 487cc to 600+, you'll definatly want some bigger and better carbs. I think some of the flatside carbs have accelerator pumps. I know somone who put a set on his 1100cc yamaha (fj?) and says the thing is WAY faster. And that's without a big bore.

Of course in the end you'll probally end up spending more than just buying a faster bike, but you already know that.
Enjoy 

Anything bigger than 79mm pistons will require replacing the sleeves. Larger sleeves require material to be removed in the cases for clearance.

I ran 33mm carbs on my 555. Ran good but could have benefited from 36mm or better yet flat slides. My 541 has 36mm.

The 4-valve head is fairly involved and potentially expensive depending on your resources. I have most of the parts and information, which I will be starting someday. Planning on using a GR650 motor though. Also, I will be using 36mm flat slides.

Megacycle makes cams for the GS. I will be sending the GSXR cams to them to be moddified for the 4-valve head swap.

Dgyver.

You have a 541? Nice.

Yeah, I'm expecting/salivating for a set of forged sleeves to go with some forged pistons, forged con rods, and a forged crank.

What about you 541, how's you get that, and about how much power are you making?

save the money and go for a 600cc

If I'm going to save up money I'm going with the B12.

But no, I'm financing that.

I don't want a 600 super sport.

I want a modified GS.

BTW you came back again?

Where do you plan on getting all this forged stuff anyways? If you get really beefy stuff, you could keep the stock dimensions, or go with a small overbore to keep everything simple and avoid headaches then just put a big ol' shot of nitrous on the thing 

Some think that nitrous is cheating, but I don't. You still have to build the engine to take it, so it's still fairly involved, but you don't need to go through the headaches of figuring out what stroke, length of rod, bore etc.

Whatever gets you off! 

That was kind of the reason behind the post.

WTF do I source this stuff?

Quote from: CirclesCenter on September 20, 2006, 06:41:21 PM
Dgyver.

You have a 541? Nice.

Yeah, I'm expecting/salivating for a set of forged sleeves to go with some forged pistons, forged con rods, and a forged crank.

What about you 541, how's you get that, and about how much power are you making?

The 541 has 78mm GPZ pistons. Wiseco stocks them. I did a post about a good while back. Have not had it dynoed, but it is about the same as the 555 which was around 50-55hp. I have no idea where to source those forged parts.

buy mine its 618 cc ready to go only $2750 come with lots o stuff!!