Do I have a rectifier/regulator problem?

[Polo]

Hi peeps.

Before I splash out on a replacement, I just want to confirm that it is the rectifier that is dying.

My battery is but 6 months old at most. It pulls in 14.1 volts when my lights are off but only a maximum of 11 when the lights are on.

Meaning a night ride ends up with me having to bump start the bike when I cut the engine. Not a problem really - it's what pillions were invented for.

Is the boney finger of suspicion well and truly on the rectifier?

Many thanks.
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My mum smells your fingers

[stinkwheel]

What bike?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Polo]

1997 CBR 900 (RRV)
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My mum smells your fingers

[stinkwheel]

Do you have access to an ammeter (a high load one, 30A+ NOT a multimeter). This can give you a much better idea of how much power is going into/out of the battery when connected in series with the main fuse.

To be honest, it sounds more like a battery problem. I'd check the battery terminals are tight and corrosion free and check for a bad connection at the reg/rec terminal block and the main fuse holder.

Also check the battery electrolyte level if it isn't a sealed one.

Any other accessories (heated grips/alarm etc.).
EDIT: Standard lights?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Polo]

Standard lights indeed. No alarm, heated grips etc. Only change, electrically, if you can call it that, is a Stebel horn.

I only know of multimeters, of which I don't own. A sparkie friend came and checked it last night and said what volts were going across it.

I will check the batter terminals etc and the rectifier. The battery is a sealed one and quite new.

I commute on it a lot, without the lights on, and it is absolutely fine. It is only with the lights on that it suffers.
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My mum smells your fingers

[Kickstart]

Hi

Check for continuity over all the stator coils.

I have had a few dead regulator / rectifiers , but in all but one case they just died completely (and the one that didn't would randomly decide to charge the battery or not).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Polo]

By continuity do you mean a regular voltage - both lights on and off?
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My mum smells your fingers

[Kickstart]

Hi

Sorry, no. With the engine off disconnect the regulator / rectifier unit. There are probably 3 wires from it to the stator (quite likely all the same colour). Check the resistance over each pair of wires and they should be the same (ie, with 3 wires A, B and C, check A to B, A to C and B to C).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[SW Motech Shop UK]

Faulty reg recs are very common on early blades. Check the bikes earths are still connected and clean and check for corrosion in the connector blocks.
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