Charging system questions

[chewy999]

I know this should have been done ages ago, before I took the engine out of the frame, but I didn't! Anyway, I wanted to check the charging system, as the voltage across the battery with the engine running was over 16 volts!

I found a Steve Saunders clip on Youtube showing how he checked the alternator by holding the negitive probe from the meter on the battery negative terminal, and the positive probe on each of the yellow wires. He said you need a reading of 4+ volts on each which I had, so breathed a sigh of relief!

https://www.youtube.com/watch?v=zOG_nmnRT5k

I then moved onto the rectifier and following the manuals specs, one way round showed an infinite reading where it should be 6000 Ohms, and when I switched polarities, the readings ranged from a low of 1.4 to 1.7 ohms where the reading should be between 4 and 6 ohms. The infinite reading may be because I have borrowed a meter from a mate and am unfamiliar with it, but the low readings suggest the rectifier may be the problem.

Can anyone with more electrical experience confirm that I do or do not need to change the rectifier, to be honest, already ordered one!

Once that is sorted out, just need to find out why my tail lights aren't working now. They did the other day, but not now. Bulbs are sound and new fuse, but for some reason they don't work, although the brake lights do. Must be a dodgy connection somewhere.

[rcmatt007]

I would expect the tail light issue is a grounding problem.... I will leave it to others to answer the other question

[chewy999]

I would expect the tail light issue is a grounding problem.... I will leave it to others to answer the other question

Thanks for that, will have a good look over on Thursday, was on nights last night so flagging now, and got to go to work tomorrow. Can hardly wait to post a picture of my finished bike, but just want it all to be working first, even if you couldn't tell that from a picture! The paintwork looks great, so pleased with it.

Forgot to say, all the other lights are working fine, apart from the small parking light in the main headlight shroud, but that may be a bulb issue, not actually checked that yet!

[bstuebing]

just replaced my rectifier and regulator with one unit (combination regulator/rectifier) that bolts up to the battery box where the stock rectifier normally sits. Unplugged and removed the regulator under the false tank and zip tied the plug so it doesn't flop around. Got the rect/reg from Sirius. It was "plug and play" and gives a nice steady 14.3 volts at 3000rpm. Previously I had almost 16 volts which I understand wasn't very healthy for my battery.

[chewy999]

just replaced my rectifier and regulator with one unit (combination regulator/rectifier) that bolts up to the battery box where the stock rectifier normally sits. Unplugged and removed the regulator under the false tank and zip tied the plug so it doesn't flop around. Got the rect/reg from Sirius. It was "plug and play" and gives a nice steady 14.3 volts at 3000rpm. Previously I had almost 16 volts which I understand wasn't very healthy for my battery.

From what I've read, to high voltage can destroy your battery. I see you have a 1000, am I right in thinking that on my 1100, the rectifier and regulator are the same item?

[mcgovern61]

I can only add that on my '82 1100, when I was reading over 15.8 volts, my RR connector was dirty. I pulled the connector, cleaned and re-seated the connector (which was harder than I thought). I also found a dead cell in my battery from overcharging. Replaced the battery and cleaned the connector. No problems since.

[bstuebing]

The 1100 and 1000 charging systems are the same. The new regulator/rectifier that I installed apparently works differently than the stock units and accomplishes what it needs to without the use of the infamous "black wire" that's in the regulator plug and that is used by the stock system to set the voltage being sent to the battery. So it's supposed to be better. Time will tell. Glad I did it and it was easy (which is important).

[CYBORG]

The rectifier is probably your problem. On your bike they are one unit . Replace it with a good used one, or you can try some aftermarket if it is guaranteed to be plug and play. Ifr you don't replace it, it will destroy a good battery. However make sure your battery is good as well

[scootsx2]

I would make sure all the ground (earth) connections are clean and tight before replacing the rectifier and/or regulator.

[jdvorchak]

Looks like he already bought a new Regulator. I would have checked the voltage on the black sense wire to see what it said. If it was around 14 v then I'm pretty sure its' just a flakey connection in the ignition switch. If it reads 15 - 16 volts then the regulator is probably bad.

[chewy999]

Looks like he already bought a new Regulator. I would have checked the voltage on the black sense wire to see what it said. If it was around 14 v then I'm pretty sure its' just a flakey connection in the ignition switch. If it reads 15 - 16 volts then the regulator is probably bad.

Will do that just out of interest, but thanks for all the replies. Just thought the readings for the rectifier, 1.4 to 1.7 may be an indication of a fault.

[jdvorchak]

You have to remember one thing about the Factory Service Manual. They judge the listed readings using a specific ohm meter that was part of the Factory tools. What I think you were measuring was in fact the forward and reverse resistance readings of a diode. The fact that you got the readings you did told me that the diode ( actually a full wave bridge rectifier ) was not blown open or shorted. Now does that mean your regulator is not bad? No! That means the rectifier is probably good but that check does not address the regulator part.

[chewy999]

need to find out why my tail lights aren't working now. They did the other day, but not now. Bulbs are sound and new fuse, but for some reason they don't work, although the brake lights do. Must be a dodgy connection somewhere.

Checked the bulbs, fuses, then started to work out where in the line the bad connection was. Found that the bad connection was the connector under the headlight that had been knocked when I put a new clutch cable on. Quick wiggle to check and as God said in Genesis 1:3, 'Let there be light', and there was light!

[rcmatt007]

ויהי אור

[chewy999]

Didn't know you could write in Hebrew!