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X-reg Funduro
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Discussion Starter · #1 ·
Hi guys,

I know the toipic of rectifiers has been covered a number of times, but in all my reading I have not found anything that matches my issues.

I have a 2000 (X-Reg) Funduro that has been sat for some time and I have been getting it ready to go back on the road. In doing so I replaced the rectifier with ebay special as the battery was being overcharged. This seemed to fix the issues and the battery started to see the correct charging voltage when running. This was just over a year ago, the bike has been sat in a shed with the better on and off the tender. Anyway, today was the day to got for its MOT, rode it to work, this is the first time its has had a proper run in a very long time. and it died on me. It started backfiring when I rolled off the throttle and eventually when I stopped at a junction in died and would not start again. The starter solenoid was clicking away but not turning over the motor. Got it recovered to work and tested the battery. It was down to 11.2V (After sitting for a few hours the battery was almost able to turn the Starter) left it on charge for an hour or so, went back to it and it fired up no bother. But when I put a multimeter on the battery it was at about 12.5v and when I revved the engine in didn't move. So I checked the output of the rectifier and it was only reading 6-7v.

Does anyone know how I can tell if its the rectifier that is the issue or if the voltage going into the rectifier is the problem?

Thanks
 

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The battery may have a dead cell as well so bear that in mind. Looks ok then put it under load and the voltage collapses. The original multi-pin blocks and cable crimps can oxidize and crumble, resulting in poor current flow. Cables can also get a bit too warm and the insulation cracks as a result. So check the easy stuff first.

You should read more than 12.5 V on a running engine. The altenator is pretty bullet-proof so given the history of the VR problems, it is likely to be that. E-Bay specials can vary so much in quality. I purchased a VR with a metal base to aid heat dissipation via E-Bay from an American outfit; motoelectrix.com. I mounted it just inside one of the RH side panel in a bit of air flow. They also supply better quality cable and connectors as the BMW ones are borderline size for what they must carry.

You will need an AC scale on your mutli-meter to measure altenator output and should be no less than 14 volt and the coil resistances for each winding should be roughly equal. There is a video on You Tube in a post I put up a while ago;
Video:
Post: Voltage regulator failed after few weeks
 

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Discussion Starter · #3 ·
It turned out it was a faulty R/R. The stator was putting out good voltage. The battery is more or less brand new Motobat. Having replaced the R/R I am now getting a steady 14.5v at idle. I have relocated the R/R to beside the air intake now. Not sure there is enough air flow there either, especially if your sat in traffic. So looking into other ideas to improve air flow.
 

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It turned out it was a faulty R/R. The stator was putting out good voltage. The battery is more or less brand new Motobat. Having replaced the R/R I am now getting a steady 14.5v at idle. I have relocated the R/R to beside the air intake now. Not sure there is enough air flow there either, especially if your sat in traffic. So looking into other ideas to improve air flow.
The later bikes put the unit in the airflow but also rain salt, etc, etc. It ideally needs a metal surface but if there is space an air convection current should be better than nothing, Under the seat, the air was pretty much trapped there. Had variable results with those batteries and have gone back to lead \ acid. A local bike dealer reckons he gets more problems in the showroom on bikes with gel batteries than lead \ acid ones if they have been stood a while.
 

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It turned out it was a faulty R/R. The stator was putting out good voltage. The battery is more or less brand new Motobat. Having replaced the R/R I am now getting a steady 14.5v at idle. I have relocated the R/R to beside the air intake now. Not sure there is enough air flow there either, especially if your sat in traffic. So looking into other ideas to improve air flow.
38211
 
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