More than 2 years after I did my mod, the story and the conclusions:
- I bought the excellent quality wire harness from [MENTION=458]bd43[/MENTION] and mounted it on the bike around Jan 2013
- I was riding this way until Nov 2013 with absolutely no problem
- back in Nov 2013 one day driving home in heavy traffic (lots of stoplights, lots of stops with engine running at idle rpm) I got home, stopped the bike. 15 minutes later I wanted to start it to move it in a different spot, the battery was almost dead (good battery, less than 18 months old)
- I charged it, but measuring the charge I noticed the voltage was low, so I went to the dealer (the bike was under warranty); they checked everything and found nothing wrong, they also tested with a different battery, relay, rotor
- in the end they removed the harness and everything was fine again
My opinion/conclusions:
- the charging in FZ6 is not good at low rpm, so I guess that's why the guys at Yamaha disabled the left headlamp low beam by removing the wire
- riding in the city at low rpm is a bad scenario for using the mod; riding out of the city is fine
- there are a couple of optimizations to the electrical consumption that can be done and it will help a bit: 1. I replaced the tail light bulb (21W) with a led lamp; saved ~ 20W and 2. running with 35W HID is not only brighter than a 50W halogen bulb, but it consumes only ~ 43W per piece; that means the consumption can be reduced fro 121W (2x50 front + 21 rear) to ~87W (2x43 front + ~1W rear); this saves 35W, reducing the risk of the dual headlamp mod to drain the battery while riding at low rpm or in bad traffic
- is the dual headlamp mod worth? Yes, in some conditions is well worth. Last year I was running at night in Croatian mountains (I was on a tour across 10 countries in Europe) and there are some 180 degree turns; the light produced by the second headlamp makes a difference.