On your turn signals, the LED's draw very little current. This makes the flasher not work because the draw is to low. Putting resisters in to make the flasher works by increasing the draw back up to the regular 27 watt bulbs. Kinda the wrong thing don't you think.
Superbright has flashers that will flash LED's without resisters. It will flash just one LED bulb or up to 150 watts of any light bulbs. It's item LF1-S- Flat. It comes with the leads ina plastic plug. Remove the wires from the plug. Now it plugs right into the stock flasher socket.
The bikes socket has a brown wire, a brown/white wire, any other wires get ignored, not used.
The flasher has a red or grey wire and a black wire. The red or grey wire plugs in the socket where the brown wire is, the black to the brown/white wire.
If your bike has self canceler, it won't work with anything but the stock flasher.
This works very well. One thing, if you have a very high output coil it makes the flasher work funny. Just keep them a foot or so apart. I hung mine on the front of the battery box.
Search Ebay for LED H-4 replacements. Lots on there. Low price few LED's, higher the price more the LED's.
Leo