Athmerbr Posted April 16, 2009 Report Share Posted April 16, 2009 I just rebuilt my bike for the second time. I am getting a very weak spark and having a hard time trouble shooting which portion of the ignition is faulty. Will not even pop with starting fluid. 4 mill, 30mm carbs, vitos head with good compression. Plugs seem wet, but very weak to no spark. Stock ignition system. How do i figure out if my stator, CDI, or something else is at fault? Quote Link to comment Share on other sites More sharing options...
Overboost Posted April 16, 2009 Report Share Posted April 16, 2009 is the gap between your flywheel and pickup coil too wide? should be about .5 mm or about the thickness of a a business card. is your stator plugged in the harness? coil pack plugged in with the blade terminals? Quote Link to comment Share on other sites More sharing options...
Jimmi Posted April 16, 2009 Report Share Posted April 16, 2009 I just rebuilt my bike for the second time. I am getting a very weak spark and having a hard time trouble shooting which portion of the ignition is faulty. Will not even pop with starting fluid. 4 mill, 30mm carbs, vitos head with good compression. Plugs seem wet, but very weak to no spark. Stock ignition system. How do i figure out if my stator, CDI, or something else is at fault? I had the same prob, check ur air gap, u can test the stator coil resistance, coil resistance, coil leads, and if all that fails, ur cdi is shagged. the values for testing is in the workshop book Quote Link to comment Share on other sites More sharing options...
banshee_terror_ Posted April 16, 2009 Report Share Posted April 16, 2009 are your spark plugs gaped right? the coil might be bad Quote Link to comment Share on other sites More sharing options...
87sheerips Posted April 16, 2009 Report Share Posted April 16, 2009 1. Unplug stator, OHM it out to factory specs (see clymers) 2. Check pickup clearance. Get that sucker as close as possible without your flywheel hitting it. I usually fold a piece of paper and use that as a gapper 3. Grab a buddies CDI if available, always good to keep one around anyways. You can get one from any year banshee and crop wires if you have to. 4. Check CDI ground wire 5. make sure Coil mount tabs are ground to bare metal. The coil grounds itself here. Stock coils hardly ever fail. Im guessing CDI Quote Link to comment Share on other sites More sharing options...
Athmerbr Posted April 19, 2009 Author Report Share Posted April 19, 2009 Thanks for the help everyone. Im headed home tomorrow so I will try all that stuff out. Quote Link to comment Share on other sites More sharing options...
Athmerbr Posted April 20, 2009 Author Report Share Posted April 20, 2009 I just went through and check my resistances. Stator black to yellow is reading out of spec at .5, do you think this could be the reason for my problems? The manual lists spec as .26 to .38 or something close to that. Quote Link to comment Share on other sites More sharing options...
bonbon Posted April 20, 2009 Report Share Posted April 20, 2009 I just went through and check my resistances. Stator black to yellow is reading out of spec at .5, do you think this could be the reason for my problems? The manual lists spec as .26 to .38 or something close to that. No, that is the lighting side of your stator. Mine measured about the same as your getting there and is out of spec but it still works. What do the green and red stripes read and the green and red solids read? I can't remember which is which but one is around 19ohms and one 119 ohms. Quote Link to comment Share on other sites More sharing options...
Athmerbr Posted April 20, 2009 Author Report Share Posted April 20, 2009 The other wires were right in spec. I will sand down the grounds for the coill and cdi and recheck those resistances. If Im wawtching a plug gap and kick the engine over with the plug grounded to the head, what should the spark look like? Does it fire mulitple times per kick and shoulld i see it well even with lights on in my garage? Quote Link to comment Share on other sites More sharing options...
fastrthnu Posted April 20, 2009 Report Share Posted April 20, 2009 as mentioned above, check your coil to flywheel gap as well. Quote Link to comment Share on other sites More sharing options...
AWR Posted April 20, 2009 Report Share Posted April 20, 2009 The other wires were right in spec. I will sand down the grounds for the coill and cdi and recheck those resistances. If Im wawtching a plug gap and kick the engine over with the plug grounded to the head, what should the spark look like? Does it fire mulitple times per kick and shoulld i see it well even with lights on in my garage? yes it will fire multiple times during one kick and you should be able to see it(or hold it in your hand...j/k)check all grounds esp.coil to frame.i always run a ground strap from head to frame.most if my electric problems have always been poor grounds or connections...good luck Quote Link to comment Share on other sites More sharing options...
lt250rfd Posted April 20, 2009 Report Share Posted April 20, 2009 The other wires were right in spec. I will sand down the grounds for the coill and cdi and recheck those resistances. If Im wawtching a plug gap and kick the engine over with the plug grounded to the head, what should the spark look like? Does it fire mulitple times per kick and shoulld i see it well even with lights on in my garage? if everything checks out with in spec check your harness for a broken wire or bad plug end. that was the problem with mine. i just checked continuity using the wire/electrical schematic in clymers book. Quote Link to comment Share on other sites More sharing options...
Athmerbr Posted April 20, 2009 Author Report Share Posted April 20, 2009 Well i pulled the coil and Ohm'ed it. The primary terminals are close to spec, but i am getting a resistance of one from each of the terminals to the plug boots. That is, the secondary resistances. That means an open circuit and that the coil is bad, correct? This is true of both sides, at the boots for each cylinder. And if this means bad coil, should I buy another stock one or is the a good opportunity for upgrade (anyone got a coil for sale)? Quote Link to comment Share on other sites More sharing options...
fastrthnu Posted April 20, 2009 Report Share Posted April 20, 2009 Stock coils are fine, and cheap. just try and find a newer one if you can help it. except one I got from minkia one time one of the plug wires fell right of the coil out of the packing box, big suprize! Ill NEVER buy from that asspipe again Quote Link to comment Share on other sites More sharing options...
Athmerbr Posted April 21, 2009 Author Report Share Posted April 21, 2009 I just wanted to make sure i was testing that coil correctly. I don't want to buy one if I don't have to. Does everyone agree that if both the secondary resistances are 1 then the coil is bad? thanks again for all your help everyone. Quote Link to comment Share on other sites More sharing options...
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