I have RK-Classic 2011. Recently friends have been telling me that my rear brake light flickers. The flickering only occur when I am moving. I have changed the brake switch and the rear light board, however problem remains. Front brake handle seems ok.
Any suggestion is causing the problem?

 

Flickering how? Flickering on with no brake applied or flickering off with brake applied?
Flickering on I'd be looking at switches. Remember you have two, one front, one rear.
Flickering off I'd be checking all wiring and plug in connections particularly under the rear fender.

 

After your repairs have failed to cure the problem,you need to check to see if any play in front brake lever to cause it not to engage switch fully. Most of the time the culprit is the front master cyl.If you can push the lever forward and the lamps stop flickering while moving,you need to overhaul or replace front cyl.

 

If your rt side hand controls have been removed or loosened with out using a shim ( as detailed in the manual) your front brake light switch may have been damaged.

that is somewhere to look- you could also look at he relay- the starter relay used is same type, you could swap and see if the problem goes away- but this is unlikely

like most things electrical, this will take a methodical approach

mike