Made myself some cheap flashers today, only cost me 8 bucks and about 6 hours work, removed bars and drilled holes 10mm apart then fitted in led stip lights that I got of eBay. The flashers work at the same speed and didn't need a resister in the circuit, it was an absolute prick getting the strips in but I eventually worked it with 5 bits of fishing line. Probably the best value for money mod I've done.

 

 

I have some red ones somewhere (old ebay purchase for a engine lighting project) - maybeez I'll try to dig them up and make a brake light.