I don't have the little grill piece installed or have a regulator in the intake duct, it's been relocated, so I was able to get an approximate measurement. Problem is I didn't have time to pull the fairing pieces needed to get a measurement to the lip of the headlight bucket, so this is to the leading edge of the fairing. "Kind of close", at best... The distance between the holes should be pretty good, but the depth would have to be assumed as bit. Someone with a bucket out of the bike would be able to be more accurate.
Two holes are arranged front to back, regulator cable runs through a large hole at the right lower edge of the bucket. Deepest hole in is approximately 17.2 CM. Closest to the front is 8.25 CM. They are approximately 12 MM right of the center join.
No idea what you're working on, but the reason I relocated mine is the aftermarket MOSFET VRRs everyone recommends will not fit. They are too thick to fit deep enough in to the intake and the holes are closer together than the OEM VRR.
97 st2 that has the original reg playing up, owner bought in a sh579 for me to fit. has a front fairing, but not sides or grille on it so i can't get the required clearance at the front for the grille to fit. so from the front fairing is fine. thanks for the info.
I removed the grille slats many years ago. For me, I think the bike looks better without them.
When I installed a MOSFET R/R, I went the hard route and did some grinding inside the air inlet as well as trying to match drill the mounting holes. Given how little heat the new R/R puts out, I would have went the other route and just shaved down the fins so that it would have fit without grinding. It would have been a lot easier.
When I changed to the mosfet, I ground down some of the aft fins, and secured the r/r with milspec zip-tie. As Tonerd said, it operates with very little heat, and the zip-ties do very nicely. I did put in heat-sink paste between the r/r and the lower metal housing, to increase conductivity. The new r/r has been burbling along at 4.2-4.5 for a couple of years now, monitoring it with my voltage meter.
Probably the old r/r would have been fine, but I was having resistance build up along the wires leading to the battery, probably because of the joints. I put in the new mosfet unit and soldered everything together, running directly to the battery. If I was going to go to the trouble of rewiring, I'd want to put in a new unit, which is not that expensive in comparison to the results of a failed unit.
Electricity is flowing, the battery is charged. Life is good.