Am I right in thinking its reg/rec failure???

Was out for a long run today on my 93 vfr750. After 100 miles I stopped for food. After 30 mins the bike started 1st try but stalled as I was leaving the car park & wouldn't start. Was like the battery was dead all of a sudden. I bump started the bike & drove 20 miles home without incident, all electrics working & the lights were normal. When I pulled into the garage I turned the bike off & tried to start it straight up but despite a strong turn over it wouldn't start up.

Would I be right in thinking the reg/rec has packed in? I have a 125 varadero & it seems they use the same reg/rec so I'll try it tomorrow & see if that sorts it. Hope so.

 

When the reg/rec fails, either the battery stops charging, or it gets over-loaded and boils out. Your symptoms do sound like a flat battery, so that could be the reg/rec, or it could be a loose battery cable, or the battery might just be past it's prime. Best to get out the multimeter and test across the battery terminals with the engine running, you should see 13.5-14.5 volts at 5000rpm, that is more than enough to keep the battery charged. If you have that but the starting problem persists, I'd pop a new battery in. In my own experience, dodgy batteries will work OK cold, and then get worse when they heat up from engine heat.

If the voltage is less than that, then look over the connections/fuse blades etc and see if something is loose/corroded, after that you need to check the stator wires. There should be 4-6 ohms resistance between each pair of the three wires. When running at 5k there should 50V AC across each pair.

 

Hmm, you mention once home, you shut it off then tried to re start , it spun over but didn't fire up. Hmm I was going to say check all switches, sounds like you have the juice. just no spark from what I read, thing is with the switches, be it the kill on the bar or the side stand, they don't usually let it spin over, maybe the master, interesting. Maybe it's a fuel thing here, just odd it was fine, then not... hopefully some one here has had the same thing happen.

 

Finally got a spare minute to take a look at the VFR. Battery has been removed & put on charge while I check things through. The Reg/Rec has been changed to a Tourmax unit which appears to be a decent upgrade from what I can find out. The wiring in the plug had melted on 1 of the stator wires so gona have to sort that. Thankfully the R/R still seems to be operational going by the multimeter so I'm hoping its just the wires

 

Cut that puppy off and solder the yellow wires straight to the rectifier
Braided lines and new tires, chain and sprockets--- that's awesome


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oh I will duccmann

 

I think I'm in business. Just 1 of the stator wires was burned but nothing damaged. Reg/rec is 100%, Stator is 100% & the battery is showing 14.2V @ 5000RPM so i'm happy. Back in business.