QuestionI have a 1975 Yamaha DT400, it ran wonderful and would always start on the first kick until last month. I can't get a spark to the plug. I replaced the coil.. I thought that might fix the problem, but it didn't work. Do you have any advice on what might be the problem? I would greatly appreciate it!
Sincerely,
Zachary Fitzgerald
zacharytdfitzgerald@gmail.com
AnswerNot a lot of internet help on Yamamamas...
http://www.bikebandit.com/parts/Yamaha/DT400B/1975
Illustrations show a CDI magneto ignition system, which is self-powered. Ignition switches and KILL switches actually put a ground on the ignition system to shut it off. So, disconnect the ignition switch and the kill switch wiring, so the CDI and the module, wherever it is are isolated from any switch devices. Check for spark. If none, the options are either a bad pulser coil, which is part of the flywheel stator assy or the CDI control module has died or is disconnected. Check all wiring connectors. Replacement parts for these things are NLA for the most part, I imagine.
The sequence for ignition is that the ignition switch is turned ON, which takes ground off of the circuit, then when the engine is kicked over, a magnet in the flywheel triggers a pulse in the pulser coil, which goes to a CDI control model, which goes to the coil. Make sure the spark plug cap isn't out of range.. usually 1-5K ohms. Always use a fresh plug to check for spark.
Go here for more help...
http://www.yamahaclub.com/forums/index.php?showforum=33
Bill MrHonda Silver
