electrics on 76 Strada

[adrian]

i had got back the fully rewound stator and remagnetised rotor, (after frying the stator due to connecting up battery the wrong way round), reassembled evrything, cleaned all electrical contacts, found the wrong connection on the headlight (a positive was connected to earth), installed only a 3Ah battery, all the electrics worked fine, lights, winkers the lot.... bike was running well, then i decided to check ignition timing with strobe, just finishing doing that when bike was revving at 6000 when there was an almighty bang, thought it was a backfire at first, but i think it was electrical, because after that, although bike still runs fine, the electrics are caput, theres barely enough power to turn the petcock on and a barely audible groan from the horn and no lights at all....also, the centre facia lamp now glows brighter as the engine is revved, whereas i don't think it did that before

could it be regulator blown up, perhaps the battery is too small and the regulator couldn't handle the power from the rewound stator, but i'm not good on electrics....any ideas would be gratefully appreciated....Adrian

[Brett]

Hi Adrian,

I think you may need to check all of your wiring for a bad connection or broken wire earthing somewhere, how old is your loom?
Do you have fuses set up? Could be very worthwhile and less expensive.

Unfortunately you will need to re check all of your main electrical components to ascertain which has blown.

Good luck

Brett

[Ralph]

May be worth looking to see if the battery has split and is dribbling acid over things.

[3potjohn]

I had a battery explode once as i hit the starter,this on a K75. I too thought it had backfired for about 1/10th of a second. By the next tenth I was off the thing hosing down and by the next tenth throwing sodium bicarbonate over it.

[adrian]

all fuses ok, battery shows no signs of leaks, but i reckon its the battery as, although it read 11.8 V, i put it on charge, charger started flashing, now that doesn't work!

the schematic diagram in my manual shows a fuse between the battery and the generator, although the circuit diag doesn't show one...is this something that anyone has got and what fuse rating? was it just that the battery was too small for my newly rewound stator ?
i've tried a 9Ah battery and the electrics are now back fine, but i'm reluctant to start the bike in case the same thing happens again....is there any protection i can build in?

[Ralph]

If you check the volts with the engine running it should not go above 14.2 ish
if it is then you could have a regulator problem. 15 amps may be a good starting
point for a main fuse you can always go bigger but if you have a standard alternator
they are about 100w so 10/11 amps with a following wind.

[adrian]

thanks, Ralph

[Ralph]

Adrian try this link then scroll to the bottom if it works
takes time to load.


http://www.rpw.it/Files/Morini_125-250-350-500_MO.pdf

[adrian]

just been for a run, came back, put a voltmeter across battery, 13.7V at idle, 15V at 6000ish rpm....connected an ammeter in line with positive battery wire, only got 1A, presumably all points to regulator problem? Would the bang have anything to do with rewired stator? I don't want to be chasing my tail?....Adrian

[Ralph]

Mine does not get anywhere near 15v it as the NLM reg on it and tops out at about 14V
dont know if this will tell you anything but the fist bit with low revs is lights off second
bit lights on, you can see the volts rise fast then level out as the reg cuts in.
I suspect the bang was the reg but only guessing.



http://s235.photobucket.com/user/G7ied/ ... 6.mp4.html

If there's been a bang then I would expect a hole somewhere, have a good look at the reg.

[adrian]

have carried out some more tests, ammeter inline with battery, i only get 2A max (maxes at about 2000rpm), and, when headlights are switched on, it shows a small discharge (i guess 2A , as headlight consumes about 4A), so how do i check output from the alternator? (As i don't want to buy a new reg if the alternator is the problem).
In the manual, it mentions a 30V and 60V check, but this would be measuring an AC voltage (?) and my meter doesn't read AC. I was advised to check for 0.4 ohms between each yellow and the red, and 0.8 ohms between yellows, but my meter doesn't go down that low, and meters that do are a horrendous price. Is there any way of checking the charging coils on the alternator with an "ordinary" multimeter?....Adrian

[norbert]

Hi Adrian,

i fear to measure AC you will nead a multimeter that can do. Normaly they cannot be very expansive. There shoud be about 60V AC between the troo yellow ones with the motor idling.

norbert

[Ralph]

I seem to remember checking mine with a head light bulb think it was from yellow
wire to earth but cant remember the details.