I purchased this tiny little voltmeter 0-99V LED display for $12.00 at an electronics market today.
exactly like this one
http://www.ebay.com.au/itm/Mini-DC-0-99V-3-Wire-Voltmeter-Blue-LED-Display-Volt-Meter-Digital-Panel-Meter-/281091909348?pt=AU_B_I_Electrical_Test_Equipment&hash=item41726226e4It came w/o the box, new, no manuf description, but I liked the fact that it really is small and compact.
Initially, I was tempted to cut into the Left side fairing just blelow the lockable glove box (just like the OEM heated grip controller) but decided, if the unit fails at any point, I would need to source the exact size replacement and may end up with a rectangular hole in my fairing....
I installed this nifty unit, INSIDE the dash, with 3M double sided mounting tape, directly on top of the ST1300 logo. (if I can't remember what model bike I am riding, I probably shouldn't be riding...)
To do this farkle;
remove windscreen
remove 2 bolts located above the glove boxes on ea side
remove mirror covers
remove 1 bolt above ea mirror, holding the dash corners
remove all poppers of top dash cover
remove 2 screws ea side of dash R and L
unplug main dash plug by pressing tabs in and carefully jiggling the plug out (2 seperate white plugs)
lift the dash unit off the bike and place on clean terry towel face down
remove 4 large screws that hold dash unit to panel / facia
carefully remove headlight adjusting knob, with 2 flat bladed screwdrivers, easy-does-it, it can be seized.
Do NOT remove the rubber switch cover for on-board computer, its a pain in the
to fit it back, if you must, then unscrew the 2 Philips screws and carefully note position of prongs and rubber gasket placement.
remove all screws on outer perimiter dash (not small internal screws!)
remove 2 screws that hold the headlight adjuster switch (failure to do this, may result in tears and big $$$)
now, carefully pry the dash front cover off the base.
important! do NOT attempt to clean, adjust or otherwise play with the face of the speedo, especially the needle it is VERY delicate!
now you can stick the voltmeter over the ST1300 logo, drill a 2.5 mm pilot hole on the outer rim of the housing, for the positive and negative wires and close it all up!
I wired it direct to my custom made, switched auxillary fuse block located in the tail.
hope you like it, took about 3 hours and looks stock!
...see pics below: