Hello. I apologize if this has already been stated one thousand times or if this is in the wrong place.
I am not a mechanic, nor am I well versed in suspension, so take this with a grain of salt.
I have a 2005 RC 51 that had a stock rear shock, stock linkage, and a 190-50 rear tire. The back end my bike seemed too low compared to the front and turn-in was suffering. So much of this effort was to address the geometry of the bike first and then to also improve handling by getting better suspension. I am aware that the front suspension still needs to be addressed.
I bought an Ohlins rear shock with remote preload adjuster, the Kyle USA linkage, and a 190-55 rear tire which is taller than the 190-50 and has a steeper profile.
The ride height adjustment advice that I could find online was to loosen the blue lock nut at near the bottom of the shock and then adjust the nut above it to raise or lower the ride height. With the shock mounted to my bike along with the Kyle linkage, I tried this method, but doing this caused the cable of the remote preload adjuster to wrap around the shock because turning that nut turns the whole body of the shock. In addition to this problem, the stock position for ride height and anything raised from that position, caused the spring of the shock to make contact with the swing arm right where the weld on the swing arm is. The answer in my situation, was to keep the shock at the stock ride height adjustment instead of turning that nut above the blue lock nut, but then instead, disconnect the bottom of the shock from the linkage and then spin the part of the shock that attaches to the linkage by hand to the desired ride height. Doing so will keep the remote preload cable from getting twisted around the shock. This however, will not help you when it comes to clearance from the swingarm. I had to lower the ride height until I saw a sliver of light between the spring on the shock and the swing arm. Note: You will not notice the clearance issue until the shock and linkage are connected completely. So you might have to disconnect, adjust, reconnect, a few times until you get it just right. My setting ended up being just slightly lower than the Ohlins came shipped, but with the Ohlins, the Kyle linkage, and the 190-55, I gained a signifcant increase in ride height. The kick stand now seems rediculously short, but it is still usable.
By the way, when swapping the shocks out or when testing the clearance of the newly installed shock, I used two jack stands on the frame (fairings were pulled in order to do this) so that I could unload the swingarm and shock while making adjustments. So a rear stand, front stand (or wheel chock), and jack stands (or some method of suspending the rear end of the bike without using the swing arm or rear tire) are advised. A friend or two can be a big help as well.
I just wanted to post this because I got quite frustrated trying to figure it out and it was at a time of day when shops were closed and I did not find the answers that I was looking for on a forum (although I would not be surprised if this exact information was available some where on this forum). I never post things, but I hope that this helps at least one person. I don't currently have pics, but could add some if this post is not immediately removed or discredited