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1978 CX500 "The Grub", '83 GL650, '82 GL500 Project "AdventureWing", '79 CX500C, '78 CX500 Scrambler
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After nolimitz' clarification, I was going to suggest that the only factor left would be intermittent contact somewhere in the wiring harness.
Great to hear it's been resolved!
 

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1981 CX500 Custom
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Discussion Starter · #22 ·
So, I it appears I've spoken too soon; the saga continues.

Picked her up today. She fired right up and idled nicely. I departed Mobile AZN's home and everything was good, and then after about 2 miles it started acting up - power cutting in and out, and if I rolled on the throttle a bit while it was bogging, it sounded like it backfired a bit. I pulled into the parking lot of a grocery store and rode around for minute or two until it kind of cleared up. Took off, rode another couple of miles where I could tell it was acting up still, and then it smoothed out and I rode the rest of the 15 miles home without incident. So weird! I have new GY6 modules on the way from Murray, so I guess I'll start there?
 

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1981 CX500 Custom
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Discussion Starter · #24 ·
So, I just spent some time trying to get the bike started, which it doesn't want to do at the moment. I was able to keep the engine going (not fully started) by keep the throttle on a bit. The left side warmed up (putting my hand on the cylinder head and the exhaust), but the right side stayed cold. I switched the cables on the GY6 units, but it had no effect - the left side continued to fire, but the right did not.
 

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That tells you that the modules aren't the problem.

Now check if the problem is the coil or the plug the same way. If it isn't any of them look for fuel problems.
beat me to it
 

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1981 CX500 Custom
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Discussion Starter · #28 ·
Thanks you guys.

These are the ones I have in it currently: Yamaha Badger Grizzly Ignition Coils YFM80

I suppose I'll order a couple more (they're only about 12 bucks a piece) and see if I have success by swapping them out.

It is, at the very least, nice to have a direction of where to look next!
 

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'84 CX650E that is evolving into a GL500
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Why do you insist on throwing parts at it instead of finding the problem and ordering what you actually need?

I'll say this one more time: Swap the coils from side to side and see if the problem moves. If it does you have found the cause but if it doesn't buying new coils won't help.

And if swapping the coils doesn't move the problem try swapping the plugs from side to side. As before, if the problem moves you have found the cause but if it doesn't you can be pretty sure it isn't a bad plug.

If none of that makes a difference it is time to look at fuel problems.
 

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1981 CX500 Custom
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Discussion Starter · #31 ·
OK, so yesterday afternoon I got in there and swapped just the coils, leaving everything else in place - I left the wires going from the rae-san to the coils in their original position/alignment, so only the coils traded places. Today after work I fired her up, and it appears that the problematic cylinder has switched to the other side. Before I did the coil swap, the right cylinder was the one that was not firing. Then I swapped coils. Today, it's now the left cylinder. Got the bike started, and it idled happily for just a moment and then started to bog and struggle, obviously running on one cylinder. I pulled the plug wire out of the left cylinder and nothing happened. Replaced it, and then pulled the right cylinder plug wire. Bike died immediately.

This suggests that I have a bad coil right? Surely it can't be anything else?
 

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Discussion Starter · #34 ·
I feel silly asking, but in case this is important, I just have to ask it anyway and won't let my pride or fear of appearing ignorant get in the way.

The ignition coil seems to have 3 main components. It has the thick spark wire that goes to the spark plug cap and then connects to the spark plug. It has a tongue-shaped (male) slide terminal that connects to the rae-san. Finally, protruding from either side of the main "barrel" of the coil are identical sections of square shaped, sandwiched-looking metal with holes in them. It is using one of these holes that I have mounted them with a bolt.

I have to ask - does it matter which side you use/mount them with? Does it need to be consistent for both coils?

Are these protrusions what "ground" the coils?

Clearly I'm lacking knowledge in the basics of wiring , but I'm trying to learn.

Sidecar Bob and DouginEasternWashtingon, I appreciate your replies. I'm really excited at the prospect of potentially killing this mischievous and maddening gremlin once and for all. It will be so nice to have a bike that is mechanically sound and finally reliable. I just want to do things the right way.

Thank you!
 

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'84 CX650E that is evolving into a GL500
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Those are the laminated steel cores of the coils and yes, that's what makes the ground connection to the bike's frame. Bolting either end of the armature will provide the ground connection but it is preferable to attach both ends for mechanical support whenever possible.
 

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Discussion Starter · #36 ·
OK, so I got the new coil installed. Started up like a dream - carburetor snappy and responsive, feeling just awesome. Go around the block a few times, still feeling great and responsive, and then it starts acting up in the same characteristic manner. Power cutting in and out and a bit of back-firing, and then the engine dies. Start it up and it's just bogging....and then the power comes back in, and goes back and forth. Limp it home. So glad I didn't go for a long ride, I would have hated to leave her on the side of a road. Ugh.

I am so discouraged. I don't know what I'm doing wrong. What do I check now? We already replaced the HALL plate of the rae-san once, and my carb was done by Larry, so it would boggle my mind if its one of those. I am so perplexed. Sigh.
 

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Well Luke, that sucks. Don’t get too discouraged yet. I don’t have any advice since I know nothing about the rae-san full hall affect system but I still think it’s ignition related and not fuel. I am sure the experts here that know that system will give you support. Hang in there!
 

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Discussion Starter · #39 ·
Ahh, I forgot about that suggestion CXPHREAK. I'll give it a try!

And Doug, I really appreciate the encouragement. I've been trying to get this bike up and going for over 2 years.....I'll keep at it.
 

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have you checked your system running voltage - a few of the gy6 modules in one batch have shown a voltage sensitivity - they work fine at high and low voltage but can be a bit iffy in the middle - there's no sense to it - but if you have a voltmeter hooked up it would be interesting to see if the misbehavior occurs in a certain voltage range. ive also seen where the kill switch can arc if its not been cleaned and has some corrosion in it - this would be eliminated by cxphreak's test.

Rayman
 
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