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Well guys, the fuel system is good, put new tire on it this morning, but it won't charge the battery. I remade all the electrical connections and ran a separate ground to the regulaotr from the battery. This regulator has been replaced at some point in time. I have red to red, yellows to stator, green to ground, and white to pink ( charge light ). All connections were poor at best. Could this have damaged the regulator? The engine sounds good and runs strong, so I'm not giving up yet. However, I may find the guy that sold it to me and perform some Texas justice.
Preston

What's the voltage at 3500RPM??

Yes, the dirty shitty coneectors can kill the regulator by overheating it. My buddy just bought a regulatpr on ebay for $5!!

It came up to 13 volts. I checked the stator voltage on acv, and got 17vac at 5000 rpm. However the charge light will not go off. I suspect it is the regulator. I rode it around afor a few minutes, and found the right fork seal started leaking, and the front master cylinder is also leaking. Can I get a kit for the master cylinder, or must it be replaced?
Preston

With 3500 RPM there should be little more, that 13V. its normal between 13.3- 14.3 V DC, but if battery is very down, then it can be also that 13.0V DC.....

That 17V AC sounds too low from alternator in that RPM, so i thing, You have to check alternator more closely... Insulation test and resistance between output wires.

Btw, still, before You managed to find "problem", take battery cables off overnight, that Your bike dont burn at nighttime for some reason.... only small advice!

Thanks Antti. I loked at the Electrex site and did the troubleshooting thing, but they only talk about Jap bikes with 3 phase alternators. They were saying 50vac at 5000rpm. I know those are higher output alternators. I checked resistance on mine line to line and found 8 ohms. Megaohm test to earth showed 0 ohms. I ordered a new regulator last night thinking this was probably damaged due to such poor electrical connections and a bad ground. I was going to buy a new stator, but could not find one. I will pull it next month to have it rewound just as a precaution
I've only had 1 other Italian bike, Cagiva Gran Canyon, and loved it, but I found electrical maintenace may be more critical than valve adjustments

Thanks,
Preston

On these old bikes the electrics are really weak, but it's enough you take care and keep clean all the connections. You can also take the connections off and welding the wires.
So, you'll avoid most of the problems.
Ciao

I had a 73 Norton Commando a couple of years ago, and I found the bullet connectors suck, so have been soldering all joints and wrapping with heat shrink. All plug in connectors, I use di-electric grease in the connections to keep the moisture out. Does anyone know what the alternator ac voltage should be on the 907?

Preston

I think, here in these sites was some post about generator output voltage (AC!!!) in higher RPMs but really cant remember, where it was. Maybe someone tested it, as i havent yet need to do so. I quess, that it should be some 70 V AC in high RPM, or some similar from 50V to 80V.....

93IE wrote: I checked resistance on mine line to line and found 8 ohms. Megaohm test to earth showed 0 ohms.

???????????????? If there is REALLY 0 ohms(or very low ohms, like 1-100 ohms) between stator output wires and ground, then Your stator is blown (insulation is smelted and wires are shortcut to earth)!!!! There must be very high resistance (high ohms, like some Mega ohms, or so)!!! If low ohms then its leaking to ground and then it cant give enough high output voltage(and surely also current) to rectifier !!!

That 8 ohms also feel "little to much", as there is only copper wire in (maybe 2.5mm wire...). It should be smaler resistance, like 1-4ohms

Are You 100% sure, that You read multimeter OHM scale right? As its normally in analog meters "upside down" ???? If U use digital meter, then you dont have to worry about reading "direction" , but connectins MUST be without any resistance, when measuring something in OHM scale....

I should have stated infinite to ground as it showed nothing with a Fluke in the megaohm range. I have a Fluke 77. I checked it again with the engine warm and found 5.2 oms between windings, but still only 17 vac at 5000 rpm. I'm thinking the stator is about gone. I found a 450 watt retrofit stator and rotor, but am not sure if it will work or not. I have another posting under stator with the link in it. I have been calling around today trying to find a used one, but no luck.
Preston

Fluke 77 have only 9V battery inside, so with Fluke You CANT make good insulation test at all !!! For insulation test You meed "Megger", or similar, what can make about 300-500V to probes !!!

Such Fluke is good and accurate for voltage, current and NORMAL resistance measuring, but it dont work with INSULATION test at all.. btw, i am electrician and i have to make such measurements daily in my workplace...

I start to be very tired to thiskind already.... sorry....

17V AC in 5000 RPM is totally too low, so propably Your stator is gone to "heaven of mc stators"... btw, new stator coast about doubble compared to regulator.... and its quite normally, that if You loose stator, U loose also regulator and via versa also.... BOTH have to be checked 100% after such happen...

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