Moderator Airhead Posted May 8, 2013 Moderator Share Posted May 8, 2013 Just got off the phone with Yamaha Corporate office in So. Calif. and the only info they could find were some general specs that confirmed what my Haynes manual has said - .27 ohms for the source coil. Where did you find 1.7? Also do you have any info. on AC voltage output as it's cranking? And finally, does your bike vary resistance as the points oopen and close? Thanks. I got my info from a DT125E parts catalog, though for some strange reason the service data pertaiined to DT100? ...misprint? I dont have any info on voltage, neither do I have a bike with points, my source coil generates around 130v to a CDI unit and measures hundreds of ohms...lots more turns than yours of couse you see a varying resistance as the points open and close...think about it! closed you are measuring a dead short through the points...open you are measuring coil resistance I dont recall you saying that you tested the HT coil and that is within specification ? Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 8, 2013 Author Share Posted May 8, 2013 Well I never thought of this until now. I messed around with the point gap. When it was at .14 I got 6 volts. Smaller than that I got 3 volts. But when I increased it I got 15 volts! I still don't know if that's normal but what an increase. At the plug that 15 volts became 48, still not enough to fire a plug. Maybe the cam that built into the housing is too worn? Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 8, 2013 Author Share Posted May 8, 2013 Well now I'm stumped. Your info and my readings say 2.7, roughly. Yamaha and Haynes say .27. My friend suggested I find an old lawnmower repair shop that's worked with the old point and magneto systems. I would believe that their numbers can't be too far different. I'll let you know. Thanks. Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 8, 2013 Author Share Posted May 8, 2013 PSI do have a new ignition coil. I'll try the old and see if I get the same voltage as the new at the plug. Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 8, 2013 Author Share Posted May 8, 2013 Boy, I just had a rude awakening. I thought charge coil and source coil were one and the same. Looking at my Clymer manual and they mention testing for lighting and charge coils and the specs - .19 and .27. Turns out those 2 coils are the 2 little coils that make up the lighting coil, they say NOTHING about a source coil. What tipped me off is the wire color - grn/wht instead of blk/wht. I can't believe I didn't catch that sooner. But even now I'm thinking 'how in the hell could they print a repair manual and NOT mention the coil that provides spark?' Incredible! Let me slap my forehead a few dozen times and I'll get back to you. Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 9, 2013 Author Share Posted May 9, 2013 For anyone following this and has a similar problem, here's a link to an interesting answerhttp://answers.yahoo.com/question/index?qid=20090422164951AAR1nus Link to comment Share on other sites More sharing options...
blackhat250 Posted May 9, 2013 Share Posted May 9, 2013 Good detective work moe " its an interesting post this... Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 9, 2013 Moderator Share Posted May 9, 2013 Yep Bk/Wh is the colour for the source coil, photos would have helped y'know Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 9, 2013 Author Share Posted May 9, 2013 Sorry about the photos but can you believe that they wouldn;t publish the source coil specs? Just the charge and lighting coil. Link to comment Share on other sites More sharing options...
moetheshmoe Posted May 10, 2013 Author Share Posted May 10, 2013 IV'E GOT SPARK! But boy have I learned a hard lesson. Not to mention time consuming and expensive. I bought new points, condenser, ignition coil and spark plug....and I didn't need any of them. If I had checked continuity when I grounded the plug against the head I would have realized that as old as this bike was the head had developed a 'crust' on it and the plug was not really grounded. I tested and tested the coils and the points thinking that was the problem. I cut and rewired, thinking that was the problem. Every one has said these old systems were pretty easy to figure out and I was just making it more difficult than it needed to be. Like they say "a little knowledge is a dangerous thing" Anyways, lesson learned and I think this bike is worth restoring. I'll post updates as I go along. Thanks Paul and everyone else who's helped. I appreciate it.Moe Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 10, 2013 Moderator Share Posted May 10, 2013 Phew, now thats great news Moe...yep you learned a lot with this one. Well done, hope you still have a comb-over at least 1 Link to comment Share on other sites More sharing options...
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