I've been getting a ton of questions about my monoshock setup on other forums. Figured I'd update this thread as well in case anyone's curious and wants to learn from my mistakes.
Fitting the GSX-R swingarm wasn't particularly difficult. The stock axle actually just kind of... fits. However the major difficulty with this one is centering the wheel. Most bikes you see aren't centered -- they're actually a couple mm off. Another major difficulty was was finding a offset front sprocket to get good chain clearance. Ended up welding two sprockets together. In hindsight I should've just measured and had a custom setup made. The rear 530 sprocket is from a 2001 GSXR 1000. It's important that I can do some canyon carving on her so I went a little overboard but very happy with the results. All-in-all I kind of should've went for a dual Ohlins setup... probably handles better... However I've heard somewhere that monoshocks get you laid.
The shock is from a 2006 Ducati 800 SuperSport -- the reason being I had wanted to install it as a diagonal/horizontal monoshock from the upper swingarm brace to the tank mount area. The Ducati has the same set-up as this. However, the machine shop I am working with was adamant that brace wouldn't be strong enough (I trust this guy -- he knows what he's talking about!). We ended up mounting down low, nearer to the axle, forcing a vertical setup and making the shock geometry a bit wonky. The stock Ohlins dual-rate spring was having issues so we swapped out to a heavy-duty spring. Works fine now.. I would say about 90% of the way there... she's now ridable with very good clearance.. however it probably could still use a bit of tinkering and fine-tuning. All in all I probably shouldn't have used this particular shock...
I've taken this is a very interesting learning experience and a crash course to shock geometry. The important point is to have the shock react at the angle it is originally intended to -- usually the shock wants to compress at a 90° angle relative to the bottom mount and overall swingarm movement. It's funny after all this I realize most of the mono builds featured on BikeEXIF are actually done incorrectly -- a lot of them aren't actually ridable bikes (too stiff or too soft).
Here's a photo of the shock mount. Its basically a series of gussets, about 2.5 inches down, connected to the stock horizontal brace/tank mount location. Originally we had created a mount directly to the tank mount -- however the bike ended up having about 3 inches clearance and mushy suspension travel. It functions well at the new location, albeit stiff.
Still missing a bit of frame strengthening in the area. I do plan to do some more hardcore riding on her so there is still a chance I will end up adding a linkage setup if I feel like she doesn't handle as well as I'd like. Unlikely, but worst case scenario will be utilizing the OEM GSXR 750 setup.