Hi my name is J.B. and I live in the Green Mtns. of Vermont.I am a builder and my wife is a nurse.No kids but we have a nice black Lab.
I have been riding since '71 starting with dirtbikes and bought my first streetbike,a Norton Dunstall 810 when i was 18.My last bike was a Honda RC51.
I just picked up a 2001 Ducati Monster 900Sie in exc. cond. with 8601mi.
I have not ridden it yet but I did ride my cousins M900 and loved the torque curve.Once mud season is over..
I see one of the first suggested mods was to drop a tooth in the front,any other suggestions?
             Thanks
              J.B.

A 900 is a solid bike, but it's 11 years old so it might need some attention.

The cam belts are spec'd to be replaced at 2 years or 12k miles. So it might need new belts.
Valve check at 6k - so that should have been done, but if not...
Fluids including fork oil should be replaced
Unless the tires are newer than the bike, they should go too.
Once that fussing is done, the 900 is a tank. I've got a 2000 900s that's at 33k and doesn't miss a tick.

And yes, it's pretty common to change out the final gearing. Either -1 in front or +3 in the back. Depending on the condition of your chain it might be time for a new one and sprockets in the not so distant future. The ideal way to do it is to add teeth in back as a 14 tooth makes the clearance around the front of the swing arm a bit tight. I run 15/42 on my 900.

Welcome BTW

Welcome John.

Stop by in NEHMA and say hi