Common Technical Issues: HONDA VFR750F (Europe)

BRAND: HONDA
MODEL: VFR750F (Europe)
YEARS: 88-89
CATEGORY: MOTORCYCLE

TECHNICAL ISSUE DETAILS
Fix Multiple / Chronic Voltage Regulator Failures ( Honda VFR 1986+) January 2, 2007 I am a motorcycle enthusiast and active rider for 35 years. Throughout the years I have restored and owned street and dirt motorcycles of the 4 Japanese marques. These projects have become my pets. I acquired a mint stock 1986 Honda VFR750F with 1600 miles and meticulous maintenance records. I'll tell you what I know and how to fix the problem after experiencing 5 voltage regulator failures all of which were replaced by ElectoSport Industries without hesitation. My only affiliation with them is as a consumer of their product / service. First, I'll review my internet research on what has been posted regarding repeated RR failures and battery charging issues. Issues Battery charging and voltage regulator issues / failures are consistently reported around 22K miles from riders of all countries. Not all riders report RR / battery charging issues. Of critical note is the fact that riders who do report failures in the UK, USA, Australia and Canada share a group of characteristics. They are: 1) They ride consistently and are likely to take significant trips of 500+ miles. 2) They ride in damp or rainy weather. This is particularly true in the UK. 3) This group includes the enthusiast who washes his bike frequently and is extremely conscious and diligent with maintenance. The complaints center on experiences with some or all of the following conditions: 1) A burnt smell while riding then reporting within 1 week to 2 months low voltage or dead battery. 2) Burned connectors between the stator and voltage regulator. 3) Vehicle does not start on restart. May start after sitting a bit. 4) Inconsistent starting - starts one day not next. 5) Slow or labored starting. 6) Vehicle dies en route to destination. 7) Drop in performance. Reports vary in area of performance drop- from low end to roll on to across the band. 8) Dim lights, blinker speed decreases. 9) Chronic Voltage Regular (RR) failures. Failures continue post system checks &/or other components replaced. 10) Inconsistent RR life once replaced Attempted Fixes Owners report buying an OEM RR. Others have replaced the unit with an after market item. Some owners have relocated the RR rearward to obtain more air contact. There are reports of obtaining a bigger unit or one with more finned surface. Additionally, some have increased heat sinking capacity with an additional aluminum back plate underneath the RR and utilizing heat sink paste. A mini fan has been added in several posters in an attempted to draw heat away from the RR. There has been a reports of using all the above mentioned approached where heat measurements before and after modification were taken. Posts were made to clean all the connectors including the battery ground cable with the addition of dielectric grease to all connectors within the wiring harness. Further attempts have been made to address the problem included replacing; the stator or other electrical components, buying a new battery, using a gel battery, adding an outboard voltmeter, using a battery charger when vehicle is not in use. I found several postings where owners were taking spare RR or battery chargers on trips as they could not resolve RR problems! Some owners simply sold their vehicles. A report on a website revealed a supplier of voltage regulators found there to be a difference between the demand of voltage between the front and rear cylinders of the Honda V-4 motor. The supplier offered an upgrade unit. Lastly, an upgrade stator is available from several sources. I did not see a posting of results using this modified stator unit. Reports from Canada, Australia, UK and my own show that these methods / attempts DO NOT solve the problem. With regularity, failures are reported occurring through model 2002. My Honda contact revealed that Honda recommends replacing RRs though they came in with alarming regularity in all years but particularly to bikes in the 22 K + mile range. Honda makes no claim to fault and places the onerous on the owner of the vehicle. Additionally, he remarked that CBR 954's were having the same problem. A search on the internet confirmed the same issue with the same rider grouping for the 954 CBR . When my 1st RR failed I went to Electronicamotos and had my electrical system diagnosed as within spec except the RR function. Subsequent failures occurred after attempting most of the above 'fixes' with a trip to Electronicamotos to have my system re-diagnosed. RR failures continued on different time lines. Each time Electronicamotos covered the unit, again testing my system. After my 5th failure and $175 towing bill, I, by chance, found an internet post from an owner who dissembled his wiring harness and reconfigured it for adding additional electrical demands after experiencing repeated RR failures. I took my wiring harness and sliced it apart. Findings The ground wire to the RR and stator is of a thin gauge. Additionally, it is crimped (not solid soldered) to all the other grounds in the electrical system (continuous loop ground). I discovered some corrosion on the crimp closest to the voltage regulator. This splice is a located at the tank seat junction. I surmise water runoff from washing or rain riding can penetrate this area. With the wiring system developing excessive heat in this area, I noticed the insulation / wrapping taped unraveling creating a zone for water collection. Any corrosion on any electrical device within the ground system will affect the RR grounding ability. = FRIED voltage regulators! As a result of this finding I made a dedicated ground from the stator / RR junction to the frame using the heaviest gauge wire I could use. Secondly, I took the battery ground wire off and inspected the attachments. The end piece attaching to the frame was stiff compared to the area attaching to the battery. Slicing the insulation away from the battery end side revealed internal corrosion with strand separation and breakage not visible or evident in any way. Slicing the frame attachment side revealed normal un-corroded stranding. I threw the item across the street. After a call to the dealer, I found myself looking in the bushes for the little turd. Item in hand I cleaned and solid soldered the first 2 inches back. I re-wrapped it then silicon sealed the end to prevent water seepage. The item was reinstalled. Once the battery was recharged a test drive revealed a return of power across the range and an end to RR failures. Conclusion: The wiring harness has a flawed ground design. The voltage regulator needs a heavy gauge dedicated ground. Voltage tests regarding the integrity of system will not reveal corrosion in the grounding system. Nothing will. Corrosion will occur with moisture present through repeated heat cycles particularly in areas that are generating excessive heat. The ground cable is internally vulnerable to repeated water penetration, excessive heat and undue flexion from battery replacement / cable movement. Internal corrosion and breakage will occur. Solid solder it 2 inches from the battery post side and water proof it. Or buy a new one and follow the drill. The 22K+ odometer reading is an important landmark as the wiring system has gone through significant heat / moisture cycles to bring out reliability issues. Paul Villalobos California

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