A couple things need to be done to the Rocket, or for that matter any Triumph and most other bikes and that is to pull every Molex connector and apply di-electric grease across the male (flat end) of the connector and replug it. Even though the connectors are fairly weather tight, the pin connectors will corrode after a time (and many washings) and produce high resistance connections. The other thing is to do the same di-electric grease treatment to both battery posts (after brightening the posts and connector lugs with fine emery paper. Finally, the starter terminals, especially the lower one that gangs down in the airstream below the starter (and rain stream if you ride in the rain) need the brightening - grease treatment as well.
I do the above to all my bikes no matter what brand. Bike wiring, unlike the underhood (bonnet in England!!) wiring in a car, is exposed and out in the moisture.