94 VFR750F regulator failure

The reg/rect on my new to me 94 VFR750 died yesterday. First symptom was total electrical failure with 30 amp main fuse going. I replaced the fuse and it blew with in a second or two - but not before all the magic smoke (which makes electrical things work if kept inside them) escaped.

The reg/rect was not a finned type and had a Honda centre code of MV4 which is not the right series anyway. The new parts from Honda have a pretty big heat sink and I have ordered a new Japanese made one from David Silvers.

Is the failure of the Reg/rect likely to be the result of some other problem or have caused any other issues?

 

R/R failures are normally pretty isolated but it it a good idea to check everything else

http://vfrworld.com/forums/showthread.php/39277-How-to-fix-common-regulator-Stator-failures

A lot of guys like to change the stator and harness, but that was not an potion for me out here in SA so I just did a couple of mods (ran a heavier wire direct to the battery, same with a dedicated earth straight to the frame and replaced all the plugs with soldered connections) which seem to be working. A voltmeter is also a good idea.

 

I agree 100% on this. It's often best (whenever possible) to change out charging system components as a group when a single component has failed (especially with hard failures). Old/original components that still test "good" (both hot and cold) will sometimes come back to bite you in the wallet after you've replaced just 1 component in the system.

 

Sounds like the PO had an R/R failure and tried a fix by bolting up one that was not right. Honda should have codes ect that will tell you which bikes the finless R/R fits. If you bought this bike from a dealer or a private party, a bit of a chat aboot backyard engineering would be in order.

They fail.. Honda knows this and they do nothing. The dealers know this and they are very happy to sell all the R/Rs in stock which they rarely have in stock.. I smell bad sushi..

One of the more famous accounts was a road test by Mitch Boehm on a VFR. The bike was a dealers bike. The R/R died. The dealer picked up the bike and Boehm. The bike was shipped back to Japan and was never seen again... All this in back issues of CW Mag.

What might be interesting is to cut out the sad stories, the fixes, what happened on a dark and stormy night and run a real poll to see how many dudes on how many VFR/Interceptors got stuck because of R/R failure.

1. BB (three)

 

Check the spade lug terminals of the 3 yellow wires into the connector for signs of thermal damage or looseness in the joint due to expansion of the lugs 'pinch', although your failure sounds more like an internal short circuit to ground rather than a loose stator phase connection. You could check the RR to see if the R/W wire is shorted to the green wire.

 

The reg/rect has had about 3 revisions since the bike came out. The latest one looks very butch with big alloy fins everywhere. I have one of these on the way.
I will check the rest of the wiring and on the alt wires will solder the wires into the spades to decrease resistance.

 

I have heard about dominatrix that are butch but never an R/R.. Is this an OZ thing?

 

If you want an example of a butch motorcycle think Harley.

 

I can do that but the thought of assless chaps around this bunch is scary!


http://www.dykesonbikesqld.org/wp-content/uploads/2011/05/MG-13-107.jpg

 

Gods wept - I will have nightmares about that.

 

Succubus on bikes..

 

Put the new reg on today and went for a 30km ride. The reg was quite hot to the touch when I got home.
New RR came with thick alloy plate and lots of computer heatsink compound was used between the plate and frame and frame and RR. The frame was fairly warm to the touch near the RR - obviously transferring a fair bit of heat.
Infra red thermo showed 80 C in the core of the RR fins. No melted connectors or other signs of distress.
I pulled apart, cleaned, soldered, and dilectric greased the RR and alternator connectors just to eliminate that. Also tightened up the female spade joints.
Ran an extra earth/negative wire from the green at the RR to the battery negative terminal and also removed, cleaned and acf-50 coated the earth location next to the riders right knee.

Will run it again tomorrow and see how it shapes up.
Other test will be to test the battery with a carbon pile load tester and see if it is munted.

 

did you use conductive grease in the terminal, or coat the outside of a connection with dielectric grease? Also with the heatsink compound--less is better. It is only meant to fill in microscopic voids and uneven areas, metal on metal is the best, too thick a layer will restrict heat transfer.

 

kenny is right on with this statement ^^^^^

 

Dialetric grease should not be put on contact surfaces that mate. Definition of Dialectric is an Insulator.

 

With any guestimated r/r failure, always pull up the red plug atop starter solenoid to check for loose or heat-damaged connections below. :grey:

If trouble is found there, just might be that r/r is OK.

BRING IT ON: Let's have the long-simmering debate about dielectric grease good or bad right here right now !! We have members on both sides.

 

I have used silicone dielectric grease on every connector I have assembled for years. I have never had a bad joint or corrosion in electrical joints assembled this way.

 

i use conductive grease made for use in electrical contacts on the battery terminals, and i use insulating dielectric grease on the non-conductive areas of connectors and on spark plug boots such as mentioned here:

http://en.wikipedia.org/wiki/Silicone_grease#Dielectric_grease

A common use of dielectric grease is in high-voltage connections associated with gasoline engine spark plugs. The grease is applied to the rubber boot of the plug wire. This helps the rubber boot slide onto the ceramic insulator of the plug. The grease also acts to seal the rubber boot, while at the same time preventing the rubber from becoming stuck to the ceramic.

...Another common use of dielectric grease is on the rubber mating surfaces or gaskets of multi-pin electrical connectors used in automotive and marine engines. The grease again acts as a lubricant and a sealant on the non-conductive mating surfaces of the connector. It is not recommended to be applied to the actual electrical conductive contacts of the connector because it could interfere with the electrical signals passing through the connector in cases where the contact pressure is very low.


Some folks have used dielectric grease within the electrical contacts and had serious problems, others are lucky and still waiting for the problems to happen...

 

There are many opinions on this subject - possibly like oil brands
http://www.w8ji.com/dielectric_grease_vs_conductive_grease.htm
But I've used it on all my bikes and never had problems.

 

So I have gone through harness and no burned connectors.
I soldered up some of the crimp connectors to ensure a good connection, removed and cleaned the main earth, also ran solder into the crimps on that. Still have wire going from reg/rect negative straight to battery negative.

At idle with new reg/rect I have 14.65v, at 3000rom this falls to about 14.15 (with headlights on) - is this normal or a problem?
Also the reg/rect reaches 70c at idle after about 10 mins. When I put an old cpu fan on it this fell to aroud 42c within a couple of minutes. Is this normal temps or abnormal?

Other than this it is running fine - fans kick in when coolant at exactly 100c and off at about 94c.