Volts off the scale

[John Roberts]

On the last climb up to Applecross on Saturday I noticed that the voltmeter on my '82 R100RS went off the scale and all the way over to the right against the stop. The lights seemed to be of normal intensity, the battery was no warmer than usual, the flashers were flashing at the normal speed- I suspect they would be flashing at a far quicker rate if the voltage was as high as the voltmeter was trying to indicate.

Could it be that the voltmeter is faulty and the voltage is OK?

As things turned out, two miles further up the pass, the wind blew the bike over as I was getting off to take a picture, in my attempt to stop it going down I broke my Achilles Tendon and thereupon lost all further interest in the voltage. Some passing bikers got the bike back up and I carried on over the top and down into Applecross where the bike is now being looked after by Judith Fish at the Applecross Inn. By now I am back home, with my leg in plaster for up to four months. Arse.

I mention that snippet of additional detail to explain why I am not in a position to give any further symptoms regarding the fault.

So, what's likely to be wrong, the voltmeter or the voltage?

 

[Thunder]

On the last climb up to Applecross on Saturday I noticed that the voltmeter on my '82 R100RS went off the scale and all the way over to the right against the stop. The lights seemed to be of normal intensity, the battery was no warmer than usual, the flashers were flashing at the normal speed- I suspect they would be flashing at a far quicker rate if the voltage was as high as the voltmeter was trying to indicate.

Could it be that the voltmeter is faulty and the voltage is OK?

As things turned out, two miles further up the pass, the wind blew the bike over as I was getting off to take a picture, in my attempt to stop it going down I broke my Achilles Tendon and thereupon lost all further interest in the voltage. Some passing bikers got the bike back up and I carried on over the top and down into Applecross where the bike is now being looked after by Judith Fish at the Applecross Inn. By now I am back home, with my leg in plaster for up to four months. Arse.

I mention that snippet of additional detail to explain why I am not in a position to give any further symptoms regarding the fault.

So, what's likely to be wrong, the voltmeter or the voltage?

OE voltmeters renowned for being faulty, either that or the regulator but given the battery did not cook that's not as likely.

Was it still giving the same reading last time you saw it?

 

[MikeP]

The voltmeter acts like a second rev counter and climbs to the red with increased engine speed?

That'll be the voltage regulator.

My mate's 80/7 that I have here did the same thing recently. I found a second-hand one cheap on ebay. Problem solved.

For your year bike, they're about £30. I imagine Sherlock will have one in stock. Or Motobins (£27 + VAT).

 

[electric_monk]

Stuff the volt meter, I hope the leg gets better quickly

 

[John Roberts]

Stuff the volt meter, I hope the leg gets better quickly

Kind of you, cheers.

Thunder: I can't be certain as to how quickly I noticed the high reading, I like to believe that I keep a reasonably close eye on it especially in remote areas such as in the Scottish Highlands, but my feeling is that it wasn't more than a mile or two since my previous check. On the other hand, that could be complete bollox, of course. What I'm saying is that, if the fault had only just come on perhaps the battery might not have had time to cook.

It was still giving the same high reading when I left the bike.

Mike: No, switch the ign. on and the needle goes straight up to the stop.

Thank you, all.

 

[John Roberts]

Update. Just been on the phone with Britannia Rescue, as I am incapacitated they will be bringing the bike down to me tomorrow, about 550 miles in all. That does rather take the pressure off the situation, as things were I couldn't be certain that a mate would be able to ride it home for me. My gut feeling is that it's just a faulty v.meter, but now I am going to have nearly sixteen weeks to arrive at a fix.

 

[nick.ct]

Sorry to hear about your voltmeter
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Speedy recovery mate

and glad you've got the bike recovery sorted

 

[Rob Farmer]

Going off the scale is quite common when the meter fails so it sounds like its kaput. Just remember if it breaks or falls off it was probably never meant to be there in the first place.

Good luck for a quick recovery. It's getting on for three months since I tore a ligament and im still hobbling about so you have my sympathy.

 

[piebaps]

Speedy recovery John

 

[Schtum]

So, what's likely to be wrong, the voltmeter or the voltage?

Little point in speculating when the real cause is so easily diagnosed. Put a multimeter set to Volts DC across the battery poles and rev the engine. If you see anything above 14.5 V you need to suspect the regulator.

Sorry to hear about the snapped tendon - sounds bloody sore......

 

[John Roberts]

Little point in speculating when the real cause is so easily diagnosed...

It will be a doddle once I get the bike home, but I was asking because I was 550 miles away from the bike at the time, and was wondering what the chances were of its being OK to ride home by a mate. As per my update above, this is no longer a problem as it turns out my Britannia Rescue insurance will be delivering it home to me tomorrow afternoon.

Thanks for your introducton to Gordon (GC), I got in touch but unfortunately he wasn't in when I called (without prior notice) at the Lochy on the fateful day on my way to Applecross. If he hadn't popped out he just might have told me that I was about to ride the highest road in Britain (and perhaps the blowiest) and perhaps I might have decided to stay at the Lochy and get drunk instead. Looking back, it would have been a much better idea!

 

[(RIP) Kaister]

if it goes full scale when the ign is turned on without the engine running - it can only be the voltmeter faulty.





...unless someone swapped the lead acid 12v battery for a fuel cell or compact nuclear generator.

 

[John Roberts]

if it goes full scale when the ign is turned on without the engine running - it can only be the voltmeter faulty.



...unless someone swapped the lead acid 12v battery for a fuel cell or compact nuclear generator.

A very good point you have there, I hadn't thought of that. At the same time it does seem counter-intuitive for a faulty moving-coil meter to grossly over read, but, as I omitted to say, the needle had been sticking, (although it was still giving reasonable readings) so a broken pivot might explain it.

Give that man a coconut.

 

[Kenny]

...unless someone swapped the lead acid 12v battery for a fuel cell or compact nuclear generator.

definately a 'must have' but I've just tried Motorworks/motobins and Sherlocks but none have heard of a nuclear generator...have you a part number

Get well soon ( well months ) John

Have a nice BMW with sidecar if needed

 

[harry]

John, to a speedy recovery.

 

[electric_monk]

It will be a doddle once I get the bike home, but I was asking because I was injured and was looking for some sympathy

FIxed that for you......

 

[John Roberts]

Weheey, the love of my life is back in the garage at last, it seems quite undamaged other than some scuffing on the crashbar and the bottom of the pannier. So, some feedback for you: it was the voltmeter. Actual voltage is fine, next stop Motor Works, thanks for the suggestions. Oh, and for the sympathy, of course, eh e_monk?