[masterjames]

Hi everyone,



I just got my 1978 CX500 last spring, rode it all summer until it died near the end - the engine would die quickly or run weak, sometimes not even start again. I checked the fuel filter, replaced the spark plugs, and finally at the end of the summer realized it's the ignition coils - you could pull the one coil and the engine wouldn't change its sound, so I was definately running on just one cylinder.



Any other ideas before I go ahead and purchase new coils? Also - can anyone recommend what ignition coils to buy?



SPECS:



1979 engine on a 1978 body, engine and bike were rebuilt winter 2010.



Thanks!

 

[81custom]

check the spark plug lead and resistor in the plug cap for correct resistance first before trying new coils - could be a simple corrosion problem.



work your way backwards in this case - plug, plug cap, plug lead, coil grounding & power leads, good connections back to CDI, good earth on CDI. etc

 

[thackney]

Switch coils side to side (make sure you change the wire from the CDI too). That will tell if the coil or something else is the problem.

 

[masterjames]

Thanks guys, I'm a bit new when it comes to troubleshooting motorcycles! I'll try those ideas!

 

[jonmcg93]

I had the same problem left would fire (weakly) right, no dice. So I swapped the connections and the right started firing. Checked the CDI.... 20 volts on right, 90 on left. CDI was toast, my ignitech is here and going on the bike this weekend

 

[bearman1]

Pull the plugs (both) ground them onto someplace other then the valve cover, if BOTH plugs have fire, you have a fuel related issue. Could be petcock, carbs, er crap in the tank itself plugging the straw filter.