Mark Ohio 1976 Posted September 9, 2012 Share Posted September 9, 2012 I have my CT2 running well, except when the headlight is turned on. The light works fine but the engine runs rough like the ignition is being grounded out. I checked the wire from the ignition switch that grounds out the coil when you turn it off, and it was open. It has a new lighting coil. When it roughs bad and I turn the headlight off it starts to run fine. Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 10, 2012 Author Share Posted September 10, 2012 I forgot to mention that I replaces the points and condenser. It seems like I might have a short in the night wiring (blue).... Not sure how it is affecting the coil source wiring though (black) Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 10, 2012 Moderator Share Posted September 10, 2012 The ig and lighting should be completely separate. The lighting switching to charging when the lights are off. The common link is the ig switch. I would look there and double check the mag for any tracking issue first. Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 11, 2012 Author Share Posted September 11, 2012 I disconnected the ground from the ignition switch to see if it is picking up a ground from it, but it still ran rough with the lights on. I inspected the ignition coil but did not find any issues. Link to comment Share on other sites More sharing options...
dt502001 Posted September 11, 2012 Share Posted September 11, 2012 How many volts ru getting from the charging if you disconnect the lighting coil ? might be a weak charge coil. as well is the battery in good shape. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 11, 2012 Moderator Share Posted September 11, 2012 I disconnected the ground from the ignition switch to see if it is picking up a ground from it, but it still ran rough with the lights on. I inspected the ignition coil but did not find any issues. No you not understanding. Its the common point in the system. The earth just shuts the engine off. If the lighting circuit which is ac is tracking across it will kill the primary voltage in the coil as that needs to be dc. See what happens if you bypass it. Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 11, 2012 Author Share Posted September 11, 2012 No you not understanding. Its the common point in the system. The earth just shuts the engine off. If the lighting circuit which is ac is tracking across it will kill the primary voltage in the coil as that needs to be dc. See what happens if you bypass it. How do I inspect for tracking? The lighting coils are brand new. I soldered the ignition wire (new) to the new condenser. The only other wire goes to the points. What resistance will the coil(@magneto) have? Thanks for the responses. I am out of town, so I won't be able to troubleshoot until this weekend. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 12, 2012 Moderator Share Posted September 12, 2012 I dont think the coils are the issue. I think the lighting is trying to earth back through the ig coil. Therby weakening the spark. How good is the earth for the headlight and the voltage regulator/resistor. What are the tested ohms values on the new coils. Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 15, 2012 Author Share Posted September 15, 2012 I dont think the coils are the issue. I think the lighting is trying to earth back through the ig coil. Therby weakening the spark. How good is the earth for the headlight and the voltage regulator/resistor. What are the tested ohms values on the new coils. I replaced the ground. Still running rough. The engine did not have a good ground, so I added one. Still running bad. The coil measured .8 omhs and the coil puts out 13 vac. If I put the headlight directly to the coil it runs rough... It's something down there.... Any ideas? Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 16, 2012 Author Share Posted September 16, 2012 The source coil measures 2.3 ohms with points open. The ignition coil measures 2.2 ohms. When i measure from the plug wire to ground it reads nothing... Open? It has a nice blue spark when I kick it over, but it won't spark my HEI spark tester. So the wiring must be fine. It's either the source coil or the plug coil... What do you think? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted September 16, 2012 Moderator Share Posted September 16, 2012 Mark ...ohms specifications are often found in service manuals and parts manuals...check your readings against them Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 18, 2012 Author Share Posted September 18, 2012 Ok. I picked up a manual. It says 0.5 ohms for the source coil. The coil reads 2.8 ohms (removed from engine). I ordered a new one. Do I need a dial gauge to set the points or can I set it to the alignment tab? Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 21, 2012 Author Share Posted September 21, 2012 I replaced the source coil. No help.... Could it be the other coil? I am running out of ideas! Mark Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 22, 2012 Moderator Share Posted September 22, 2012 No point wasting effort about being out of ideas thats the whole point of the forum. Take a breath, kick the tyres, have a cuppa but clear your head and we will get there. Just back up a minute and bear with me. You said you put the headlight straight to the coil and it rsn bad. Do you mean you connected the headlight to the ig coil. Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 22, 2012 Author Share Posted September 22, 2012 Thanks for the encouragement! No, I connected it directly to the headlight coil, bypassing the ignition switch. How is the engine grounded to the frame? I am wondering if grounds are an issue. Maybe the lighting coil is finding ground through the ignition coil and back to the frame... My other theory is that the spark is weak and it gets weakened even more when I pull current from the lighting coil. Wires are new from ignition coil to plug coil... The spark would not jump the gap on my HEI spark tester. That may require more spark than this bike was designed with. Thanks for all the help! Link to comment Share on other sites More sharing options...
flyday58 Posted September 22, 2012 Share Posted September 22, 2012 This is what one guy found: Member Posted 30 September 2011 - 05:32 PM it turned out to be the same problem I had on my replacement ignition switch This post from shows it in detail..... Its just that I purchased a new ignition switch from yambits the other week, fitted it and the bike would NOT start, no matter what I tried. everytime i turned the key to ON it was being grounded, yet everything checked out fine until I turned the key... you can see the culprit arrowed, I simply moved the leg away from the solder and it all worked. whats the chances of it happening twice??? glad to have been of service! So removing the ignition switch and giving it a thorough check would be worth it. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 22, 2012 Moderator Share Posted September 22, 2012 This is the thing, yamaha's even right into the 90's generated all the power they needed for the ig with out affecting any other systems. The lighting as a result should have no connection whatsoever, the only places they come close are the ig switch, which you bypassed. Also the flywheel. Thing is there should be no connection to the headlight. Can i ask if you have 2 or 3 coils in the mag. Secondly which ones are you using for what? The lighting is deffinately affecting the ig but it should not be able to. Link to comment Share on other sites More sharing options...
Moderator Cynic Posted September 22, 2012 Moderator Share Posted September 22, 2012 This is what one guy found: Member Posted 30 September 2011 - 05:32 PM it turned out to be the same problem I had on my replacement ignition switch This post from shows it in detail..... Its just that I purchased a new ignition switch from yambits the other week, fitted it and the bike would NOT start, no matter what I tried. everytime i turned the key to ON it was being grounded, yet everything checked out fine until I turned the key... you can see the culprit arrowed, I simply moved the leg away from the solder and it all worked. whats the chances of it happening twice??? glad to have been of service! So removing the ignition switch and giving it a thorough check would be worth it. Was my first suggestion but he said he has bypassed the switch and gone direct to the mag with the headlight. And still has issues. Link to comment Share on other sites More sharing options...
dt502001 Posted September 22, 2012 Share Posted September 22, 2012 I would like to suggest you remove the light switch from the handle bar and see if it runs better. Possibly the wires are alowing some voltage to ground. also check the wireing as it travels through the bucket again possibl alowing volatage to ground The eng is grounded buy just simply being in contact with the frame as with the ign coil, stray volatage on th grounding side of the coil could be causing your problem. Also you never mentioned the state of your battery? Link to comment Share on other sites More sharing options...
Mark Ohio 1976 Posted September 22, 2012 Author Share Posted September 22, 2012 So I finally decided to expose the wires from just above the air box that runs back to the rear fender. I was reading higher resistance on the black ground wire, so I replaced it. I don't think that was the issue. I also found that the red wire going to the diode was not connected to anything(. The battery would not be connected to take a charge). I had put a newer blade style fuse on the battery positive wire, but I did not know the original fuse was in the back protective boot. After a test drive I found it to work! I added an additional ground from the battery ground point to the ignition ground point. Any ideas why the night charge not being connected would cause such an issue? I have 3 coils in the magneto, all three have been replaced. I guess the good thing is that I have gone over all of my wiring now! Link to comment Share on other sites More sharing options...
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