I bought a low mileage 916 about 2 months ago that had sat in storage untouched for a few years.
This was stored with all the fluids as it was tracked one day, put in storage, and then for some reason never touched again until I bought it.
I am still finishing some things on it but this is what I have had to do so far, keep in mind the bike had less than 1800 miles on the clock, so everything that was needed was more or less due to time sitting.
The list so far:
First, all the fluids had to go.
Clutch: reservoir drained and cleaned, lines fully flushed and fluids replaced
Front and rear brakes: reservoirs drained and cleaned, lines fully flushed and fluids replaced. Pads were good and yours will be as well
Oil and filter drained and replaced. (If this is clumpy at all then do the oil change twice to ensure there is no sludge left. Suggest a cheap oil in the first change, put a few miles on it and dump it, then put in your higher end oil.)
Air filters had literally deteriorated over time, and all were removed and replaced
Fuel lines were like decomposing inside of the tank, this required me to replace all the fuel lines, the connections (went with metal quick connects) and the entire tank cleaned out. I lucked out here and there was no rust, just deteriorated lines.
Gaskets on the exhaust were like a composite fiber or something and looked broken down, so I swapped those out as well with metal ones.
New tires, they sadly looked brand new… but age had clearly caused hairline dry rot.
New belts
New battery
New sparkplugs
All the connections needed to be gone through and checked, bolts, screws, clasp, clamps etc. Replace whatever is worn, rusted, or noticeably aged.
Chain lubed and adjusted
Check suspension (mine needed no adjustment, and forks luckily weren’t leaking)
And finally cleaned and washed up.
I still want to replace hoses and a few other things but I’m up and running now.
Quite a bit of work for just sitting in storage.