persistent surging solved by cleaning fuel injectors

After a layup of a couple of months over the summer, my 1150RT developed a surge across all rpms. It accelerated smoothly and normally, but at all sustained rpms there was a noticeable stumbling. I examined the spark plugs and just to be safe replaced them, checked the air filter, which looked ok, did a throttle body balance using my homemade manometer, which included cleaning the BBSs. Still no improvement. Drained most of the gas, put in new non-ethanol with a good dose of Techron, but after going through most of a tank still no improvement.

Then thought of the fuel injectors. I pulled them from the cylinders and ran the starter; they just dribbled. At that point considered mailing them off to be cleaned, at about $18 a piece, but as I'm going to be traveling the next month wanted to find a way to clean them myself. I found this method on Youtube:

I differed from the presentation by using small alligator clips on the electrical contacts, being careful to separate them with electrical tape so there'd be no short. I found a small 9 volt battery was enough to activate the solenoids, the kind of battery used in smoke detectors. That was a lot easier than using a 12 volt, and I didn't know whether that would have supplied too much juice and have caused damage to the injectors.

The cleaned injectors when tested gave robust spurts when reinstalled on the bike, and the bike ran as good as ever on a test ride. No surging at all, except around 3500 rpms in the lower gears, and that minimally. I should add that I redid the throttle body balancing, but it hardly needed any adjustment. Apparently even when clogged the injectors were closely balanced.

Great tip, especially the link to the video. Thanks. Bookmarked for future reference.