The dynamo on the 16H had recently been overhauled (previous owner) but when I rode the by yesterday for the first time since the rebuild it wasn't working.
I tested it as one normally would (bridging the terminals, bulbs and blipping the throttle) ... no joy.
Cleaned the commutator and brushes, tested it, worked a treat.
Today, no apparent charge through the ammeter.
Tested it again, no joy.
Checked the commutator again, gave it a once over just to be sure.
Retested it and ... no joy.
Is there anything else that I can do to identify/rectify the problem?
TTFN
Ian

Hi Ian,

you can go over the leads and see if there are solid connections and a good earth,
And also check if the brushes move freely in there guides
And does not get stuck, and that the brush springs are not too loose.

Noam.

email (option): noam10@gmail.com

Have you connected the battery correctly with the correct earth? Will the dynamo motor if removed and connected to a battery? (it will only motor slowly as it is wired to charge a battery not act as a motor) if it does the problem may lie with the regulator. I usually find that the reg box needs its contacts pushing down as they get a slight oxidisation on them and if you push them down they usually spark and it just breaks through the oxidisation and it will usually work from that point onwards. You don't say if it has an MCR 1 or 2 or if it's an Indian copy one.

email (option): davmax@ntlworld.com

I have one particular dynamo that will only kick into charge when i manually close the cutout points, then it will work for the rest of the day but not the next. I'm going to try a clip under the ear next time!

Hi Ian,just a thought,are you trying this with the lights on ?.I would presume that your battery is in good condition,so once it is fully charged,and there is no drain on it,that would indicate your regulator is doing its job.
cheers Rick

email (option): richardholt@rocketmail.com

The "Motor Test", I'd forgotten that !

Right then, tested it and it motors so I now know that the brushes and commutator are fine.

Just a thought ...
I remember on another bike, thinking that the dynamo was faulty and only after replacing it did I find out that the star clutch on the fibre gear was slipping. I'd rather not dismantle the timing side right now, but if needs must and I can make the time it'll be worth checking.

Thanks
Ian

I've triple checked the Earth and that all OK.
The regulator is an original MCR1 which hasn't been tested yet.
I cleaned it up before fitting, but as I haven't been getting a charge from the dynamo when doing the bulb test, I haven't progressed through the charging system.

My thoughts were:
If no charge indicating on the ammeter, then ...
Double check the wiring.
Test the dynamo.
Check the regulator.

BTW.
The battery is new and fully charges and I have replaced the ammeter as well.

TTFN
Ian

Have you re-polarised it? Ron

http://www.wdbsa.nl/lucas_dynamo.htm

email (option): ronpier@talk21.com

Rick

Hi Ian,just a thought,are you trying this with the lights on ?.I would presume that your battery is in good condition,so once it is fully charged,and there is no drain on it,that would indicate your regulator is doing its job.
cheers Rick

email (option): wariron@tpg,com,au

When he rebuilt the dynamo did he internally wire the dynamo positive or negative earth? To check it, when you motor the dynamo it should rotate in the direction of its travel, if it isn't it needs to be internally rewired.

email (option): davmax@ntlworld.com

Yes, repolarised it

I have just tested the dynamo by removing it from the bike and revolving the armature with my cordless drill 1200 rpm.
Not sure that 12oo rpm is sufficient though.
Bridged the F & D terminals and run them to a bulb and then out of the bulb to the dynamo casing
Result = not even a glimmer.
Mmmmm ..

Just checked for direction of rotation and it rotates in the direction of the arrow on the casing when wired up as negative earth.

Don't know if this might be relevant. Mine stopped charging and I could think of nothing beyond all the previous excellent suggestions. Did them all but still no joy. A pal suggested it may be crud between the segments 'bridging' them. I had previously cleaned them with a clean rag and switch cleaner as part of my previous checking. However, I prepared a suitable plastic scraper and gave each groove a thorough scrape. Although the segments had appeared clean quite a large amount of gunge was in the grooves between them. Hey presto one working dynamo. It is important not to cut away any of the insulation and ISTR a diagram in my manual showing the correct depth etc.

Ah, but then it probably wouldn't motor, and he said that his motored. So I'm guessing it is the regulator at fault.

email (option): davmax@ntlworld.com

Done that already

But I'm not getting a charge when doing the "bulb test".
I haven't even started to look at the regulator.

However, in the meantime I have noticed that the whole magdynamo until rocks when the engine is running. I checked all the securing bolts etc to no avail. Then popped the cover off the magneto chain and could see that the chain was as tight as a ducks rear end. No wonder it was rocking.

Now that the timing chain and gears are off, I'll remove the timing cover and investigate the star clutch.

On second thoughts, there's no need to check the star clutch until I can confirm that the dynamo is working. So I'll just sort out the magneto chain tension, reset the timing and investigate the dynamo again.
Phew !

Try spinning it up much faster, I can usually only get a few volts at that speed. I kept pulling one apart with an apparent fault but in the end the drill speed was upped to max and suddenly 20 volts.

Ian it's easier to do your bulb test with the dynamo on the bike and engine running. You could also check the rotation issue. You said it motors in the direction of the arrow.....But is it the correct dynamo (arrow rotation) for the bike. As already suggested it might just need the wiring swapped round inside? Ron

email (option): ronpier@talk21.com

I did the bulb est on the bike.
First time it failed, then I cleaned the commutator and brushes and it worked a treat. I tested it a number of times that day and all was OK
Next day when I took it out for a ride it failed again.

Regarding arrow direction ... I'll have to look into that.

What puzzles me is the fact the fault seemed to be corrected and then reappeared.

Ian

Ah I must have missed that bit. The fact that it lights a bulb and motors when off the bike, suggests regulator. Is it solid state or original? The solid state ones will not stand any form of abuse. One crossed wire or flash and they are often destroyed like a fuse. The originals can have points issues as already mentioned. I have fitted the solid state type from 'A O Services' (Alan Osborn) on some of my bikes and never had a problem.

Or maybe it's as simple as a poor connection on your dynamo/ammeter/regulator. Ron

email (option): ronpier@talk21.com

The problem I'm having is that when the dynamo initially didn't work.

I did a bulb test on the bike = failed
Cleaned it up and test again on the bike = pass
Double checked later in the day = pass
Went for a ride = failed
Did another bulb test on the bike = fail
Cleaned it up again and tested on the bike = fail
Checked correct earth wiring = pass
Flashed it for negative earth and bulb tested on the bike = fail
Motor test off the bike = pass
Checked motor test and direction of rotation = correct (?)
Spun the armature at 1200 rpm in cordless drill = fail

Mmmmmm?

Ian

As suggested, spin it up with higher revs and give it a clip on the ear to show it who's boss!

Revved it up to 2400rpm to no avail.
Also checked direction of rotation and that is correct.
Mmm??
Ian

Time to give it the a dynamo guy! Ron

email (option): ronpier@talk21.com

Hi Ian,

According to the workshop manual,
The "Long" dynamo, (E3L) should provide 7V @ 1050 to 1200 R.P.M.

As you mentioned few times that all works after cleaning the commentator,
May be the brusher are the problem?
I mean there are hard brushes, soft ones, with or with no copper in the mix..
If you have another pair of brushes, I would give it a try.

Another thought:
If you short the "F" and "D" terminals, and instead of connecting to a bulb
Just short it to the dynamo's body and then spin the dynamo with your hand,
(NO POWER TOOS! As soldering could melt and armature coil could burn if generating )
You should feel resistance, as the dyno is generating and the potential
Is shortened to the body.
When you un-short, the armature should turn freely.
This is also an indication of if the dynamo is generating .

Good luck,
Noam.

email (option): noam10@gmail.com

Tried that and failed again :-(
I'm passing "my dynamo man" tomorrow as it happens, so I'm inclined to drop it in to hime for a "once over" and be done with it.
Thanks
Ian

Noam Zehavi

Another thought:
If you short the "F" and "D" terminals, and instead of connecting to a bulb
Just short it to the dynamo's body and then spin the dynamo with your hand,
(NO POWER TOOS! As soldering could melt and armature coil could burn if generating )
You should feel resistance, as the dyno is generating and the potential
Is shortened to the body.
When you un-short, the armature should turn freely.
This is also an indication of if the dynamo is generating .

Good luck,
Noam.