I have an 04 S4R with 20k miles on it. I haven't ridden it the last two years, but make sure to run it every couple months. I've taken it around the block, changed the gas in it and stabilized, kept the battery on a tender etc.
I remember even when I was riding it that it was difficult to get it started below 55 degrees, but now it won't start unless I put a space heater under the oil pan for a good hour beforehand. Then it starts up with few issues.
Is the problem, the old oil? Stabilized gas (some of it is old even though I've run, siphoned, topped up)? Spark plugs that I haven't changed in 4 years? Fuel filter?
Any ideas? I'm trying to sell the bike, and it's scaring people off.
All of the above are likely, but start off with load testing the battery.