Single and dual spark F650GS / G650GS have 2 wire flasher units but there are differences in the connectors. The SS uses 1/4" (6mm) spade connectors. The DS and G Series have 1/8" (3.2mm) connectors and socket.
All can be converted to LED indicator lamps by replacement of the flasher unit, but there is a problem with the wiring of the dash indicator lamp on the F's. A solution is written up below. With the standard flasher unit, LED's can be utilised in either front or rear indicators but not both. If LED globes are fitted to both, then the indicator system will act much like a 4 way flasher with one side a little dimmer than the other. See the dash lamp modification below.
The 2010+ G Series and Sertao flasher relay is the same as the F Series Dual Spark. The Dash Mod is not needed.
LED indicator relays and indicators may not be high on the mod list but the move enables indicators in the hand guards and far more importantly coupled with LED tail and parking lamps they can be used for extended periods in a roadside emergency 4 way flasher situation without flattening batteries.
Small 3 wire unit with adjustable flash rate. It fits in place of the existing unit but requires running an earth wire. Known to work well
Larger 6 wire auto cancelling unit. For use with R series momentary action switches.
Need to disable the locking mechanism on the indicator switch
Lower cost 2 wire unit,there are many similar units under other brand names. Probably the best option, 2 alternatives to fit Single and Dual Spark models
BMW have placed the dash indicator lamp across the left and right indicator power wires on the F Series so the non active indicators act as an earth for the dash lamp. There are a few solutions to the problem.1/ Remove the Dash indicator globe and rely on looking at the front indicators to check they are operating or use small LED lamps from your local electronics store to mount left and right indicator warning lamps in a location of your choice (in the rear of front indicators ?). Considerable work and modification of the dash panels is involved.
2/ Make a 2 LED indicator lamp with each LED operating to earth to fit the existing lamp holder. This is a painful and fiddly process, but it is possible, providing left and right indicator warning. For the brave only.
3/ Put a diode into each leg of the wiring to the dash lamp. Connect the other ends of the diodes to one side of the lamp and earth the other side of the lamp. This is the most practical solution.
There are commercial kits available to do this conversion. See Kuryakin.com Diode Kit
There is a write up on the diode solution in a thread by Coletrain at F650.com F650.com Thread
An enhanced version of the thread with added information is available as a pdf here Dash Lamp Diode Mod
Single spark on the left, dual spark on the right.
The differences are positioning in the electrical box,
the size of the relay and the size of the connectors.
The STD indicator globes are 10 watts
LED compatible relays are lower in cost and
are a better choice than the BMW relays
The 2010+ G Series and Sertao are the same as the Dual Spark
Many solid state flasher units have been placed on the market since this page was written, many would be suitable for use on the F650. Size will be the critical factor. One high quality miniature unit is mFlash from motogadgets
The 3rd wire on the majority of 3 pin flasher units is an earth wire, many of these 3 wire units can be used simply by extending the 3rd wire to earth. There is a write up on hazard flasher diode repairs in the repairs section.