VFR750 reg/rec info

[JBSmith]

I once stumbled across a website that had a lengthy discussion about the (some would say chronic) regulator/rectifier failures suffered by the VFR750, and possible causes and solutions. Damned if I can locate it now. Can anyone help?

TIA


JBSmith

[Mrs. DantesDame]

Check over at VFRD (http://www.vfrdiscussion.com/forum/index.php?) Gobs of VFR info over there

[Saucy Jack]

VFRD is heavy on solutions such as mounting extra fins and cooling fans, and adapting R/Rs from other bikes. Way too much work. Get the latest R/R from Honda. It can easily be recognized by its heavily finned metal case--a different design from the original.
 
The basic problem with the VFR750 R/R is that is was designed to shed all of its heat into the subframe via metal-to-metal contact between the backing plate on the R/R and the subframe's steel mounting plate. However, this design relies heavily on the two surfaces being flat. Any air gap diminishes the ability of the interface to conduct heat and results in deadly heat build-up in the R/R. Because the subframe mounting plate is only 1/16" thick or so, it may not stay as flat as required through fabrication (which includes welding) and assembly. So, production lines being what they are, the two surfaces don't always mate as the engineers planned.
 
The new R/R from Honda addresses the problem in two ways--kind of a belt and suspenders deal. First, it is supplied with an extra mounting plate that fits between the R/R and the subframe. This plate, maybe 1/8" thick, significantly increases the contact area on the subframe, and it can flex enough when the R/R is torqued down to join the surfaces properly. Second, the R/R's case is now heavily finned metal, so additional heat can be dissipated directly.
 
I've had the new R/R on my VFR for more than four years and 20,000 miles without a problem. Before that, I went through three or four of them in 44,000 miles. And I've never heard of a failure in the new R/R in a healthy charging system.

[dinolee]

vfrdiscussion.com had a database meltdown on Dec 5th, 2006.  A lot of the  information in the posts are incomplete now.  Miguel is working hard to get it restored, but there is a chance that a lot information will be lost for good.  

[tbzep]

VFRD is heavy on solutions such as mounting extra fins and cooling fans, and adapting R/Rs from other bikes. Way too much work. Get the latest R/R from Honda. It can easily be recognized by its heavily finned metal case--a different design from the original.
 

A big reason for adapting R/R's from other bikes is because the OEM R/R's are expensive for the VFR.  You can often get an R/R from often crashed GSXR's, R1/6's, CBR's thanks to squids, stuntas, and newbies who twist before they think for a small fraction of the cost of a new OEM R/R.  I think the guys that researched it said that even the new ones from those bikes were significantly less than a VFR R/R.

You can't just plug-n-play with them, but if you're capable of cutting and crimping/soldering a few wires, you can spend the money you saved on safety gear or farkles.  

[Aero]

I know that some VFR owners mount a computer cpu cooling fan directly over the R/R, wired into the ignition circuit to ensure a constant flow of cooling air. This would probably prevent R/R failure in most cases.

[paularthur]

I've had two VFR's (1991 & 2000) and have ridden with several.  The R/R problem is notorious.  Here's the definitive fix:  http://www.electrexworld.co.uk/#1X0.  The problem, I believe, is the rotor winding insulation, for what ever reason, decomposes causing shorts thereby raising the voltage at the rectifier frying it over time.  A new rotor from Electrex has fixed all the VFRs I've heard about (including mine)...permently!