Nice bike. One of the few/ rare 900 SS I see.
The forks, as best I can deduce, are basically the same as the one on the 750 Sport, the M1BB. 40mm fork tubes. While not a horrible fork, there also wasn't much praise heaped on it. Fairly basic, and no adjustment to speak of. The good thing, (or bad thing) is those forks are pretty special that they fit your bike and are set up for 17" front wheel and 4 piston calipers. Good reasons to make them work better.
First of is to take them apart to see what you have inside of them. If the damper rods are disconnected or broken, then its pretty plain what you need to do. Fork springs can also break, giving you very little spring force.
One alternative is to go to some aftermarket stuff. Top of my list is the Ricor folks that do make a product for a 40mm fork. Could be your fastest/cheapest way forward.
http://store.ricorshocks.com/
Of course there is the matter of just setting the forks up in the first place.
1. proper fork spring rate
2. sag / preload (on your bike, thats adding preload shims)
3. Damping adjustment (which on that fork, is changing the weight of the oil)
Search the web for some good technical papers on what you should do.
Remember:
- Only one change at time - so you know the cause and effect.
- Take lots of notes. What was the set up, and how does it feel and ride?
- Take your time
- Do the back as well as the front. ( as stiff shock in back will make the front feel soft, and visa versa)
- Find someone who knows what they are doing to help
If all else fails. Take it to a good suspension shop. I live in the SF Bay area, so I have about 3-4 good choices, but in more rural areas, you may find a good shop hard to find.
Can you tell us a bit more about your bike.
- What weight fork oil did you use?
- What is your sag set at currently?
- How much do you weigh?
- Do you know what the fork spring rate is?
- Have you taken the forks apart already?
Cheers, Phil