YSS installed on 2010 650R
This thread is over a year old, but I just installed the YSS shock in a 2010 650R. I bought the adjustable model (MZ506-285TRL-09) because that seems to be the one that is readily available in Bangkok. It can be adjusted in the range of 280-290mm, so it's at the extreme end of its adjustment range to match the stock 290mm shock length. The non-adjustable version is part # MZ506-290TR-09. Both come with a 180 newton-meter spring (red and black colors are available).
The 24mm locking nut on the length adjuster is on extremely tight from the factory. You need a beefy 24mm open-ended wrench to loosen the nut along with a 22mm wrench across the flats of the upper shock body to prevent the shock from rolling while you loosen/re-tighten the nut.
I supported the bike with a pair of jack stands under the foot pegs (very steady!). You'll also need to lightly support the rear wheel, so that it won't abruptly drop to the ground when you remove the shock bolts. The bolts need to be re-tightened to 44 ft-lbs. The upper shock bolt has a small rubber washer as part of the assembly. The shop manual seems to indicate that it's supposed to be replaced when you re-assemble, but I just used the old one.
I had to increase the pre-load slightly to get 30-35mm of sag. I have no idea where to set the rebound damper. It's currently set to 25 clicks in (out of 60 clicks) from fully damped.
I paid about US$335 for the shock at current exchange rates. I didn't want to invest $600-$900 for a Penske/Ohlins. I don't race the bike, so I'm sure that the YSS will be a big improvement over the cheap stock unit for street use.