How much time do want to devote to this project?
On my 950smr I've used a local RaceTech shop for the shock re-valve and did the fork myself. I've had the fork apart many times chasing a workable setup that is better then stock. The shock has been redone several times as well. I've enjoyed learning about my forks and suspension but that time may have been better used ridding. I would have sent my stuff off to someone who had developed a better big SM suspension setup but couldn't find anyone who had at the time. I'm into my second year of working on this on and off.
I'd suggest using someone who has gone through the learning process on other bikes like yours. SPS or Slavens seem to be quite well respected for 990adv forks. Their experience is what you're paying for, not fairy dust. It takes time to do the development on an improved suspension solution. You can either pay someone for their time or use your own time.
I wasn't trying to save money by doing the forks myself. I looked at it as a learning opportunity. Fact is by the time I purchased the tools and supplies needed I was close if not over the cost of having a shop do the re-valve. In addition to the list previously posted you'll need a good quality micrometer to measure shim thickness plus inch-pound and foot-pound torque wrenches.
If you do decide on the 'Kit" approach, Moto-Pro is great to work with as well as Slavens. I wasn't too impressed with RaceTech. I've been well pleased with RaceTech for my road and race bikes but they've missed the target so far on my SMR.
Word to the wise, Use the exact same fork oil to start with. Changing oil has a huge effect on dampening. Oil brands actual viscosity vary a dramatic amount. Don't buy based on the weight of the oil, it is not a reliable measure across brands. Meaning 5wt oil from brand A won't be the same as brand B 5wt, not even close. Also be very well versed on the impact of changing your rebound, compression adjuster, and spring pre-load settings prior to taking things apart. Be sure you have set sag correctly and document the best stock setup you've found.
At 24k miles you should strongly consider replacing your bushings as well as seals. SKF seals offer a massive improvement over stock, Slavens carry them plus sell KYB bushings that are a excellent quality lower cost option to the WP bushings.
If you decide to do the work yourself I can provide a fair bit of useful information. Hit me up.
nattyMo screwed with this post 01-10-2013 at 07:36 AM