Hi folks I have a new to me 1974 Ducati GT750. As the title suggests the system doesn't seem to charge the battery and I am not running the headlight. I am getting 14.0 volts at the baterry at 4000 rpm so it seems like the alternator is generating the voltage. I'm not to sure the best spot to test the load while operating, any suggestions? I'm thinking about swapping out the regulator as it appears to be stock. For the cost($100 Can) it seems to be worth doing to remove that in the possible culprits.
The battery is brand new and appears to be in good shape. I know the rotor and stator have a reputation for being weak but that repair is pricey and will have to get deferred until the winter if it is necessary.
Battery Losing charge
Hi Bern,
A couple questions first. Is the battery losing charge while sitting or while you are riding it?
Check to make sure that your brake light is not stuck on while you are riding.(mine used to, killed the battery fast).
What is the charge at the battery while it is idling? While at 2000rpm, 3000rpm?
Check the voltage at the battery while the bike is running and idling and see what happens when you apply the brake to activate the brake light and or turn on the headlight. I'll guess that your voltage will drop below 12 and closer to 11.5. At this rate of charge your battery is dieing.
Also, just because the battery is "brand new" don't blindly assume it is good. If you can, have someone do a load test on it to make sure. If it were dropped at the warehouse it could have a shorted cell and wouldn't hold a charge. Speaking of that, if you take it out of the bike and charge it does it hold the charge? A load test will tell you for sure.
Unless you are riding the interstates all of the time you probably aren't running the bike at 4000rpm very much. If you ride mostly around town in the lower rpms and use the brake a lot your battery is probably not getting a sufficient charge.
Your regulator is most likely good because you are getting 14 volts at 4000rpm and not more. The regulator does just that. It regulates your voltage to not exceed a certain amount. It appears to be doing that.
The alternator conversion is not as expensive as you might think. Watch E-bay for a rotor (the magnet part) from a 1998 Ducati ST2. It's a bolt on fix. That's all I have done to mine. I still have the original regulator and stator. When I took the stock rotor off the magnets wouldn't even pick up a screwdriver. The new rotor with the rare earth magnets tried to grab every tool I had out.
If you were to spend some money I would spend it on the rotor replacement, not the regulator.
Here is a link to some of the alternator conversion info.
http://willyg.homelinux.org/Alternator/
This is pretty detailed but the bottom line is that the 1998 ST2 rotor bolts right up.
Hope this helps,
Let us know,
Dean
Some pics of my fix.
A couple questions first. Is the battery losing charge while sitting or while you are riding it?
Check to make sure that your brake light is not stuck on while you are riding.(mine used to, killed the battery fast).
What is the charge at the battery while it is idling? While at 2000rpm, 3000rpm?
Check the voltage at the battery while the bike is running and idling and see what happens when you apply the brake to activate the brake light and or turn on the headlight. I'll guess that your voltage will drop below 12 and closer to 11.5. At this rate of charge your battery is dieing.
Also, just because the battery is "brand new" don't blindly assume it is good. If you can, have someone do a load test on it to make sure. If it were dropped at the warehouse it could have a shorted cell and wouldn't hold a charge. Speaking of that, if you take it out of the bike and charge it does it hold the charge? A load test will tell you for sure.
Unless you are riding the interstates all of the time you probably aren't running the bike at 4000rpm very much. If you ride mostly around town in the lower rpms and use the brake a lot your battery is probably not getting a sufficient charge.
Your regulator is most likely good because you are getting 14 volts at 4000rpm and not more. The regulator does just that. It regulates your voltage to not exceed a certain amount. It appears to be doing that.
The alternator conversion is not as expensive as you might think. Watch E-bay for a rotor (the magnet part) from a 1998 Ducati ST2. It's a bolt on fix. That's all I have done to mine. I still have the original regulator and stator. When I took the stock rotor off the magnets wouldn't even pick up a screwdriver. The new rotor with the rare earth magnets tried to grab every tool I had out.
If you were to spend some money I would spend it on the rotor replacement, not the regulator.
Here is a link to some of the alternator conversion info.
http://willyg.homelinux.org/Alternator/
This is pretty detailed but the bottom line is that the 1998 ST2 rotor bolts right up.
Hope this helps,
Let us know,
Dean
Some pics of my fix.
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Steve Foster
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Regulator did the trick
I installed a new regulator and that seems to have done the trick. I ran the battery down today by leaving the light on. The battery was reading 13.5 volts before and 12.2 volts after being run down. I then took the bike for an hour long ride with the headlight on and the battery quickly recharged and was sitting at 13.35 volts when I checked it last. The plugs were nice and clean even after a period of low idling, previously with the old regulator they were fouling if the revs were kept low.
The bike pulls better at low RPMS as well. I noticed that the voltages were higher when the bike was running at low RPMs even with a drained battery.
I bought an ADC6000 regulator on ebay for 89.00. Much cheaper than going down the newer version stator route.
The bike pulls better at low RPMS as well. I noticed that the voltages were higher when the bike was running at low RPMs even with a drained battery.
I bought an ADC6000 regulator on ebay for 89.00. Much cheaper than going down the newer version stator route.
Regulator did the trick
Hello all
I have the same problem as Bern,and i would want purchase a ADC6000 regulator on ebay.
My bike is a Duc 750 GT 1973.
Please can you tell me if the installation of this item is simple,or this needs to modify the electrical system?
I have the same problem as Bern,and i would want purchase a ADC6000 regulator on ebay.
My bike is a Duc 750 GT 1973.
Please can you tell me if the installation of this item is simple,or this needs to modify the electrical system?
Alternator Change
The original regulator has 6 connections the new one I used has 5
Old New
Alternator 1 Alternator 1
Alternator 2 Alternator 2
Alternator Center Tap
Positive 1 Positive
Positive 2
Negative Negative
Charging Light
The Orange wire that is connected to the second positive circuit off of the old regulator runs the lights and horn when the ignition switch is turned to the left. Given that there is only one positive circuit on the new regulator I chose not to use this feature. If you wanted to I'm sure you could connect the orange to the positive on the new regulator if you use a properly rated diode in between.
The only thing you need to do is change the old spade connectors on the old wiring to bullet connectors. The positive and negative from the new regulator attach straight to the battery which, schematically, is identical to the old circuit.
At the end I have the following wires capped and insulated. The old orange and red from the bike to the regulator, the centre tap from the alternator, and the charging light wire from the new regulator.
Hope this helps.
Old New
Alternator 1 Alternator 1
Alternator 2 Alternator 2
Alternator Center Tap
Positive 1 Positive
Positive 2
Negative Negative
Charging Light
The Orange wire that is connected to the second positive circuit off of the old regulator runs the lights and horn when the ignition switch is turned to the left. Given that there is only one positive circuit on the new regulator I chose not to use this feature. If you wanted to I'm sure you could connect the orange to the positive on the new regulator if you use a properly rated diode in between.
The only thing you need to do is change the old spade connectors on the old wiring to bullet connectors. The positive and negative from the new regulator attach straight to the battery which, schematically, is identical to the old circuit.
At the end I have the following wires capped and insulated. The old orange and red from the bike to the regulator, the centre tap from the alternator, and the charging light wire from the new regulator.
Hope this helps.
Sorry the site removed the spaces
The original regulator has 6 connections the new one I used has 5
Old -----------------------New
Alternator 1 -------------Alternator 1
Alternator 2 -------------Alternator 2
Alternator Center Tap --Not used
Positive 1 ----------------Positive
Positive 2-----------------Not used
Negative -----------------Negative
Charging Light-----------Not used
This should be more clear.
Bern
The original regulator has 6 connections the new one I used has 5
Old -----------------------New
Alternator 1 -------------Alternator 1
Alternator 2 -------------Alternator 2
Alternator Center Tap --Not used
Positive 1 ----------------Positive
Positive 2-----------------Not used
Negative -----------------Negative
Charging Light-----------Not used
This should be more clear.
Bern