Fried the wire between diode board and battery on my V50

[lc4dakar]

Got back from a 5 mile ride and noticed the wire between the diode board and the starter connection (which is a junction that also has the wire to the battery) was totally fried.  Melted all of the insulation on the full length of the wire and slagged parts of the wiring harness sheath.
Checked the diode board and there was only one bolt holding it to the frame.

I searched, and all of the burned wiring problems seems to be on other wires going out of the diode board.

Is this a diode board problem or a grounding problem?
Or a voltage regulator problem?  All of the wires and connections at the regulator look normal.

[Groover]

I think the diode board may have shorted to the frame with there only being one bolt. Two of the bolts are isolated and are +, the other two are ground and can touch the frame. I'd say put the bolts back on, be sure you have those insulator thingies in place and try again - my guess, that is the only problem.

[Kiwi_Roy]

I searched, and all of the burned wiring problems seems to be on other wires going out of the diode board.
 

I assume the wires just terminate at the diode board (straight in - in straight out) there is probably a short going to the switch or from switch to fuse block (the schematics on line don't show it but often the switch feed terminates on the diode board).  
If it was a short in the diode board it should just burn the wire between battery and board and not the wires heading out of the board.

I highly recommend adding a 30 0r 40 Amp in-line fuse at the battery connection, I do that on all my bikes, better to blow a fuse than have it go up in smoke.

[SED]

The burned off insulation is a result of the battery grounding - the generator cannot put out the current to do that damage.  I'd guess Groover is right put is back and see if it works.  ;-T

A couple of other checks after re-attaching the diode board as suggested; replace the wires and then check the battery voltage at with ignition off.  Maybe charge the battery.  Wet cell battery will show about 12.8 or 12.9 volts fully charged.  (After sitting about and hour - battery voltage will be higher right after removing from the charger and voltage will decrease for an hour or more after removing from the charge)  Voltage might be 13.0-13.1 if using an AGM battery.

If battery voltage is less than about 12.5 the battery is badly discharged.  Charge and reconnect and ignition.

Ignition off battery should show 12.7v to 13.0v.  Ignition on it will probably drop a little.  At 2500rpm battery voltage should be about 14v+ and less than about 15v.  If it is less than about 13.4v I'd suspect a diode or alternator winding. If battery voltage doesn't change from 12.8-13v at idle to high rpm it's probably a bad connection (fuse?), bad diode board, bad regulator or bad alternator or multiple causes.

hope this helps!