Just sorting out the electrics on my mid-80's 650 project bike. The CDI units are standard Bosch 1 217 280 034 units. The coils are Tec MP06. The wiring diagrams and parts lists refer to resistors between the CDI units and the coils. Other posts in this forum refer to 0.99 ohm resistors. Do these coils need resistors, or was that just for the Bosch coils which I think were used in very early systems? On the coils, one terminal is green and the other black - anyone know which is the power feed and which the trigger feed? Or doesn't it matter? The electrics are a real mess on this bike so anything is possible!
Sorry. I don't know if the MP06 coils need resistors. With regard to the polarity, if you have it the wrong way round the spark will jump from the body to the electrode instead of the other way round. This would probably be ok and you might never notice but the spark will jump easier from a fine point than the blunt surface.
The early systems did not use Bosch coils, but Nippon Denso coils number 129700 (80 mm bolt spacing) as per this photo: The resistors were Bosch number 0 227 900 002. In the workshop manual, the resistance value is given as 0.9 Ohms.
Thanks - that's really useful info. I am planning to replace the Bosch CDI units with a twin-circuit Horse Power Ignition one (https://www.hpi.be/item.php?item=CD6905D) which should drive the coils fully without the need for resistors - but I had better check with HPI first. Has anyone had experience of the HPI unit??
Good-looking product - thanks. Pricing looks about the same level as the HPI, and a recommendation is always a good thing!
