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Hey guys. As this is my first post in the forum, I want to start by saying thanks for letting me lurk about and take advantage of all of your knowledge and expeience prior to my actual post.

Before I describe the actual problem I figure I may as well describe the bike just a bit so you have the background. I have a 1979 cx500c that was actually given to me about 20 months ago. Prior to me owning the bike it had been sitting for about a decade with very little work or running in betweeen. Last summer I had another friend (who knows his way around motorcycles) help me get it back on the road as well as cutting the rear subframe and lowering it a bit. Once we had the bike looking about 80% like we wanted it I decided it was time to get it on the road. It wasn't too many miles in that I realized the right cylinder would cut out a when I was accelerating hard. A bit more experimenting led us to believe that there was a carb issue and that this one side wasn't getting the fuel it needed to run right at speed. Carbs were pulled apart and cleaned again, but this didn't fix the issue. So we purchased new carbs and rebuilt these to match the pod filters and open exhaust system, but still no improvement. I pulled the resistors from the spark plug caps and they were replaced with the "brass rod modification" as described on this forum. We also adjusted the timing chain (using the tensioner bolt) and made sure that the valves were set up correctly but I still have the same issue. I also had the CDI resistance test run (more on this later).

Symptoms are these: Bike starts with the first bump of the starter and idles pretty well even when cold. Runs great, but when wrapping up in all gears there is a certain point where the right cylinder just cuts out. It seems to be about the same spot in all gears, and is somewhere between 50 and 55 in 5th gear. The crazy thing about it is how well it runs right up to that point, and that it just is that one side that goes out.

After testing (and sometimes replacing) most of the non-elecric potential issues (and an email to Murray, initially about a potential investment in his Mikuni carbs) we started looking at the electical. Running the basic test on the CDI came back with normal results for all but the connection from 3, LH Adv Pulsar to 5, Ground. This didn't produce a reading at all.

So, the question is, where do I go with the motorcycle from here? Is the answer an ignitech replacement for the CDI? Or, is that not the right place to look? Any suggestions would be helpful.

Thanks again for the help.
 

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Hi, I'm surprised you didn't get any answers on this. I actually turned out with the same problem today. I haven't check anything yet on the bike, but I had the same problem years back with another cx and the ignition cable wasn't connected properly. The fire would cut out of the blue, on and off. Your problem seems electrical, but I'm not a senior. I will check that first, the connections.

Have you switched coils to see if the problem was still on the right?

let me know where you're at, it might help me!
 

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You might have a spark jumping from a crack in the plug boot - I know mine was doing that. I had to replace the boot which negated my earlier and short lived resistor mod.
 
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