I had the same problem on my 89 Shadow. Tried cleaning the switch several times, but the fix was to replace the OEM flasher unit with a new electronic flasher from superbrightleds.com. Cost was $11.95 including shipping. The one I bought was the Universal Motorcycle Electronic Flasher--LFI-S-Flat. The OEM has three wires, and the new one has only two, but it was plug and play on the Shadow. Never has a slow cold morning turn signal again.
Not sure if the Valk uses the same unit, but it is a Honda, and the flasher is "Universal."
A search for Turn Signal Flasher turns up lots of threads. Not sure if what I did on the Shadow is the same. Below is one of the threads that talks about the flasher. May be best to clean your switch first, and if that doesn't do the trick, then think about replacing the flash unit.
http://www.valkyrieforum.com/bbs/index.php/topic,89219.0.htmlGood Luck.