I've been looking at the GS motor to hop up for a long time now and it always seems to come back to the cylinder head... Everytime I read a GS vs. EX article the EX's 4 valve head is what adds the legs. No matter what you change e.g. exhaust, carbs, porting - you'll still have a 2 valve motor running against a 4 valver. :guns:
I've read about the GSXR head conversion as often as I come across it and while it seems fairly involved, has anybody looked at "boxing it up" as a kit? Would it be possible to make up a kit like this in a home shop and sell it for under a thousand dollars? I have all the equipment to do it in my garage.
Has anybody ever looked into this?
Perusing ebay, you can pick up a used GS for under $1000. If you added a $1000 4V head kit you might possibly end up with a GS corner carver that's close to the EX on the straights for about $2000 dollars.
To preempt the naysayers - I understand it would be simpler to just go buy a xxxsportbike blah blah blah but I don't do things that way.
There was this guy that did the conversion on his Race-GS. But because of the added power he kept breaking cranks. Even with a fluid damper mounted the cranks would still break after some time. So I guess the engine is at its design limit already and would need major redesigning to take the extra power reliably.
But maybe it's possible to use the EX engine in the GS. Would be a nice combination of power and handling I think.
if you want a faster/better....buy a faster /better....why piss up a rope
also water cooling has a bunch to do with the ability to get more power.
bobbroussard has done the gsxr head thinge..
email him.
ok, the guy that kept breaking cranks had it punched out to 650cc . the biggest problems i would think is the custom cams that would have to be made. not as simple as trimming off the ends. figure wouldnt really need to stick with just GSXR, could go with GS750e aslong as you use the 81-84 4valve head. but again, custom cams are the issue.
GS750? Custom cams aren't too bad of an issue I guess. Do you know if either config (GSXR or GS) allows use of the stock pistons? I realize that there will be some displacement needed to process air through either 4V head... But cams wouldn't be too bad if they didn't also require custom pistons...
Bob B's motor is running 77mm custom J&E pistons that have a GS bottom with a GSXR top.
you can go bigger bore if and use the new breathing holes to thier potetial.
but i believe the older GSXR1000 1027cc? sleeves fit in the cases with minor machining and you can just use the stock GSXR pistons/rings. Custom ground cams would be needed for the adapted head as its a differnt fireing order for one. i think a differnt lift and duration would be needed aswell as the newer valve train is laid out differntly and wouldnt work very well if at all. though i could be wrong on that.