My wife and I bought a 2008 Anniversary Edition 1200 Sportster earlier this year. The bike has 8500 miles on it and my problem is with the motor sputtering in the higher gears.
So the bike sat for about 2 years without much use, but when it is driven, and no so much in the lower gears because the throttle is on more, but once I get to 4th and 5th and am cruising with only a little bit of throttle rolled on the motor will spit and sputter somewhat, kind of like having moisture in the tank and the motor doesn't run smooth.
As far as I know there has been nothing done motor wise and I have ran several tanks of fuel through it riding. My question is, is the problem possibly a fuel injector issue or the fact that it sat for awhile could running fuel injector cleaner through the system straighten out the issue or is it something else. Any ideas would be a great help.

 

Put in some Seafoam and run through a tank. I think you have to use 2 oz. per gallon for your purpose but check the directions on the can.

 

Also, what do the spark plugs look like?

 

I have not looked at them, but I will check.

 

will the machine hammer on, aka run to redline in the gears?? if so, fuel delivery should be ok. two things off the top is check vacuum hose condition for the map and check the O2 sensor for a lazy swing or locked (should get a code for that one).
also intake leaks.

 

Yes the bike will run to the redline no problem. I do not have any error codes but I will check the other things you suggested also.

 

Check the fuel filter. If the bike sat for 2 years theres a good chance the gas in the tank did some damage to the internals of the tank. Fuel filter and sock are usually the first to go.

 

Yeah we took it to the dealer to have the 10,000 mile service done and thought perhaps some of these things would be taken care of. I think I will get all the parts mentioned and swap them out. Thanks all for the info.