I was looking at pics from this article: http://www.motornieuws.be/be/nieuws/eerste-test-swm-superdual-avontuur-voor-een-prikje-4503 It describes the Super Dual, which is a 630 in "adventure" clothing. This pic caught my eye: Is that a knob to adjust the spring pre-compression? (just below where the body panel meets the tank) I know the KTM 990 adventures have one. If it is, I want one! :-)
If you google or ebay search hydraulic preload adjuster there is new and second hand options . The ohlins on a early 90s cagiva elephant even had one . Just buy whatever diameter suits your shock and what orientation /packaging fits your frame
