little dave Posted March 29, 2009 Share Posted March 29, 2009 on my 1974 dt175a. recently i started blowing headlights at higher revs. i checked my charging circut output and its about 4v at idle. 20v at high rev (6000 rpm) unless i hook up the batery, then i maxes out at 8v i checked the headlight circut the same way and now im getting no output thru the low beam. and less than 1 volt at 6000 rpm on the high beam. I cannot keep driving it without some help because i might cook my battery. what part do i need? i assume its some sort of voltage regulator. but, there isnt one that i can find. I have traced all the wires from where they exit the flywheel to the headlight switch and battery. there is no regulator. no box, no nothing. is that (the voltage regulation) controlled within or behind the stator windings? my bike has 3. a fatter wired one at the bottom, and two thinner wired ones at each side. in a ring. please help... is it possible that i blew the stator coil for the headlight? Link to comment Share on other sites More sharing options...
little dave Posted March 29, 2009 Author Share Posted March 29, 2009 nevermind. after taking off the flywheel, doing a complete wire trace, breaking out with the volt tester, checking volts, and resistance, taking apart the switches. I said screw it. i would have to find the part used. since i knew that the low beam was popped, i switched to high beam. put it all back together and started the bike. wouldnt you f-ing know that it worked fine? I pulled off the light plug again and tested the two low and high. both at 6-7 volts at max rev. now my high beam position switch is a lil wonky (it flickers, and dosent always make contact), so i swapped the wires in the plug so that i could run the high beam bulb in the low beam position. that will do for further testing purposes and for now until i get another bulb. i noticed some oil in the area where the flywheel is kept. im thinking that perhaps that was what contributed to the problem. I know that there is not supposed to be oil there, but hey, that would be a time consuming fix. its not that bad right now and i can live until i get it rebuilt someday when it reeealy needs it. Link to comment Share on other sites More sharing options...
Madison Motorsport Posted March 29, 2009 Share Posted March 29, 2009 It sounds like the regulator has failed. Link to comment Share on other sites More sharing options...
little dave Posted March 30, 2009 Author Share Posted March 30, 2009 It sounds like the regulator has failed. any ideas where i can get one/some. my bike is blowing headlights again. Link to comment Share on other sites More sharing options...
little dave Posted March 30, 2009 Author Share Posted March 30, 2009 ran an ac volt test on my headlamp circut today. 8-12 volts at idle and 40 at high rev. i cant keep a headlight at all. whats wrong with my bike? (it was a fuse) found out what it was. I learned a-lot (more than the guys at the local shop) heres what i found out thru trial and error. if the charging circuit is disconnected from the battery, or the battery frys, the output voltage on both the charge circuit and the headlamp is uncontrolled. i had blown a fuse that i put inline on the charge circuit. as a result, the battery wasnt hooked up. blows headlights. i put a meter on and 18-20v at idle, 30-40 volts at rev on both the charge circuit that is rectified to dc and the ac headlight circuit. hooked the battery back up and the same circuits run at 5-8v dc for teh charger and 6-14.8v at headlamp ac. unplug the battery, and its back to uncontrolled voltage. put a 10a fuse inline instead of a 3a fuse that i had installed before to avoid overcharging the battery.( or at least not putting more than 3a into it) everything is normal now. I think that at some point, the light coil was rewound perhaps even the charge circuit. to be 12v. but with a 6v diode it charges fine and accepts a 12v headlamp. go figure. Link to comment Share on other sites More sharing options...
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