bike_rider Posted July 9, 2014 Share Posted July 9, 2014 hello all, i am having trouble getting spark from my 1979 dt125f and after checking the all the wiring (including the coil, the rectifier, the ignition/kill switch, the ground, cleaning the condenser/points aswell as the coils) and when we checked the voltage coming out of the magneto, it only topped out at about 4-6v. and when searching around we found that it is way too low, so we checked the wiring inside the magneto and it all seems good (in terms of resistance and continuity) between the four contact points and the ground. Are we missing anything? Any help will be greatly appretiated Thanks in advance Link to comment Share on other sites More sharing options...
dt502001 Posted July 9, 2014 Share Posted July 9, 2014 Hang tight the dt experts will be along but I think a 79 dt had a 6v charging system. Are you getting any spark? EDIT: ok so a 1979 dt did have a 6v charging system quick search for a regulator told me that, if you getting a week spark then change the condenser for a new one,well thats the first thing I would do , and set the point gap. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 9, 2014 Moderator Share Posted July 9, 2014 I agree it is way to low for the ignition source coil...I assume you measured the voltage from that eh? was your meter switched to AC volts? Link to comment Share on other sites More sharing options...
bike_rider Posted July 10, 2014 Author Share Posted July 10, 2014 Thanks for the replies, And yes that was checked in ac volts from the source coil Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 10, 2014 Moderator Share Posted July 10, 2014 well then I'd say a new source coil is required Link to comment Share on other sites More sharing options...
bike_rider Posted July 10, 2014 Author Share Posted July 10, 2014 When I told my dad that I might need a new source coil he asked me if there was a test to verify if it is in fact the source coil that is bad. Long story short, is there a test that will confirm that the source coil is bad? Or is it just the low voltage? Thanks again Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 10, 2014 Moderator Share Posted July 10, 2014 yeah the test is to see if the resistance is within acceptable tolerances of specification Bk/whi_Gnd should be 2.14 ohms +- 10% come to think of it 2.4 ohms cannot equate to many windings at all so now I'm thinking that 6v may not be all that un-realistic after all 1 my 175 with cdi has a resistance of 130 ohms...many many more windings then and a far higher voltage developed, in excess of 100v if I remember correctly Link to comment Share on other sites More sharing options...
dt502001 Posted July 11, 2014 Share Posted July 11, 2014 If all or any of the windings test low on the ohms to ground then it is the windings, Think about it this way,,, if the windings are touching ground then the power to ground will be a easy flow to ground out and not work to send the power to the coil. Link to comment Share on other sites More sharing options...
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