GT750 J charging issues

[busa1300]

Several questions on the charging system of my 750J....
Will a GT750 run without a battery? I have a RZ350 which will run with no battery as the generator keeps the ignition firing
If a GT750 can run without a battery, then I have a charging problem. (although I just read that the generator does'nt really put enough power out at idle to possible keep any power to coils)...?
Trying to get a bike running to the point of determining if I should invest more $$$ into it, or pass it on as a project to someone else. I rebuilt the fuel tap, rebuilt the carbs, inside of tank is now spotless, and new points condenser. Put a battery charger onto the hot battery wire and the ground cable to the frame.....and it fired right up, running on all 3, smoking away. I turned the charger off after bike warmed up a couple minutes, and the bike shut down too.
Are there any scanned pages of a service manual to explain the checking process of all the possible parts that could be a problem. Or is there one specific part that usually goes out before anything else?
I am guessing this is the reason the bike has been banished to countless garages and barns for the last 20 plus years....

If anyone can direct me.....thanks...

[jabcb]

The RZ350's alternator has a permanent-magnet rotor. Its output doesn't depend on a battery.

The GT750's alternator has a field-coil rotor. It won't produce any output to start the bike unless the field coil is powered by the battery. The alternator starts to produce enough output to run without using the battery at around 1,300 rpm with the lights off, but only if the battery initially powered the field coil.

GT750 alternator output curve is shown on page 18 of: http://www.ozebook.com/compendium/suzi/suzidata1.htm

[busa1300]

I guess I need to invest in a battery then....
And take it from that point.

Does that mean if the bike would have a dead battery, I could not be push started or kick started?
Thanks for the help in direction.

[tz375]

Correct. It needs battery power to fire up and it needs battery power to create a magnetic field in the alternator field coils.

[busa1300]

I put a well used and near dead battery from my project 86 gsxr in the GT. Charged it up for a bit, and the bike fired right up with a hard kick. Unhooked charger and let bike warm up, and it ran unbelievably good. Since it was running on it's own power, I had to take it down the road....carbs leaking like crazy the whole time. Damn.....!!!! my RS250 pulls like a monster, my RZ pulls like a full size bike...so I know two strokes, but this GT750 really surprised me on how good it pulled. Especially for a 40 year old barn left over... I think I might be keeping this one, and get a little more serious about cleaning it up.
Thanks for the info to help me get this far with it.

[busa1300]

I figured out why carbs leaked....
All the floats were leaking fuel in them....made them heavy, and kept needle open.