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Discussion Starter #1
The right cylinder lost all power and went out on the way to work this morning. No smoke, no weird noises.

Mods are as follows:
- Murray coil on kit
- Murray carbs
- Free flowing exhaust with shortys
- Rae-san ignition (installed by Murray himself)
- Engine has around 35k

The bike has run very strong for the past year. I did all those mods last fall. I've taken it on a few 1k miles trips and it has never done something like this.

I checked the carbs, they are spotless inside.

There is some oily goob at the end of the right exhaust. When I start it now, some faint white smoke puffs out of the right cylinder. It comes in and out, but very weak when I rev it.

Any ideas on what it is? Thanks in advance fellas.

I can provide a video upon request if that would be helpful.
 

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Discussion Starter #4
I replaced the spark plugs an hour ago, but it made no difference then. But of course, now I walked out and it started up fine. I don't have my compression tester here at the house, but I'll try to get one today.

Old spark plug:
Screen Shot 2019-11-18 at 10.40.07 AM.png
Screen Shot 2019-11-18 at 10.40.37 AM.png
 

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Discussion Starter #6

It's running decently here, but the cylinder was completely dead with no response just an hour ago. It reminds me of a bad coil, but the oil is scaring me. (plus the coils are brand new)
 

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Discussion Starter #7
Limped it to a coffeeshop just now. Ran strong for 3 or 4 miles, then cut out. Pulled over for a few minutes then it kicked back in. I'm at a loss. It has spark for sure.

I ordered a new GY6 boxes as some of the terminal were dirty..just as a shot in the dark.

Going to swap the coils themselves to see if that is where the problem is or not.
 

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Discussion Starter #9
the rae san looks to me like its not blinking right on one side co,pare teh strong green to what looks like a weaker one

i just sent you the coil drivers

it does look a bit oily or not ridden hard enough
I noticed the weak blinking as well. I'll give those a try. Thanks Murray! I ride her pretty hard, got to keep the harley's on their toes :)
 

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Oil seems like it might be a symptom rather than a cause on the plug. If a cylinder drops out with no compression, the rings are no longer going to seal as well as normal. Combustion pressure typically forces them against the cylinder wall to seal. Without that pressure, oil will get pulled past the rings and into the cylinder.

However, if your dead cylinder was dropping out due to lack of spark, I would expect to see the plug completely soaked in fuel, because you will still be sucking air (and fuel) in through the carb. It almost seems like you are sucking one carb dry, and then after you shut the bike off it will slowly refill and run fine for a bit until the level drops again. You might try opening the float drain to see if you are getting good fuel flow; let it drain through for a while and see if flow slows down. Probably worth doing a visual check on the bowl vents, since I have seen clogged or pinched vents cause similar symptoms as well.
 

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Discussion Starter #11
Oil seems like it might be a symptom rather than a cause on the plug. If a cylinder drops out with no compression, the rings are no longer going to seal as well as normal. Combustion pressure typically forces them against the cylinder wall to seal. Without that pressure, oil will get pulled past the rings and into the cylinder.

However, if your dead cylinder was dropping out due to lack of spark, I would expect to see the plug completely soaked in fuel, because you will still be sucking air (and fuel) in through the carb. It almost seems like you are sucking one carb dry, and then after you shut the bike off it will slowly refill and run fine for a bit until the level drops again. You might try opening the float drain to see if you are getting good fuel flow; let it drain through for a while and see if flow slows down. Probably worth doing a visual check on the bowl vents, since I have seen clogged or pinched vents cause similar symptoms as well.
I honestly thought the same thing with the carbs, but I pulled the carb off and the float bowl was full (checked twice after it died, wouldn't start back up for a while). I think murray is on to something with the LED's being different, there is something funky with power supply. I'm going to switch the GY6 boxes today to see if that swaps sides. If not, I know its either carb or cylinder issues.

What you said about the spark plug having fuel makes sense as well. I'll check my constant flow with the fuel on to see what it puts out. I'll report back my findings.


BTW, love your build. I romped my CX on a 1000 mile 5 day off road trip this year with a group of vintage dual sport guys.
 
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Yeah ... but oil ingress generally happens on the vacuum stroke.

Oil dilution with fuel is more likely in the scenario given.

I am wondering if perhaps there is a minor headgasket blow into the oil drain or the head chambers for the original breathers.

I think a leakdown test needs to be done.

The plug is an irridium. This doesn't help with diagnosis but the plug may be saturating the insulator causing the plug to short and stop firing. A spark test on the plug itself immediately after the cylinder cuts out would also be instructive.

There is always the wild card of the oiled plug and the shutdown being unrelated.

The shutdown could also be a thermal intermittent on an ignition component and the oil a bad stem seal on the intakes.
 

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Discussion Starter #13
Yeah ... but oil ingress generally happens on the vacuum stroke.

Oil dilution with fuel is more likely in the scenario given.

I am wondering if perhaps there is a minor headgasket blow into the oil drain or the head chambers for the original breathers.

I think a leakdown test needs to be done.

The plug is an irridium. This doesn't help with diagnosis but the plug may be saturating the insulator causing the plug to short and stop firing. A spark test on the plug itself immediately after the cylinder cuts out would also be instructive.

There is always the wild card of the oiled plug and the shutdown being unrelated.

The shutdown could also be a thermal intermittent on an ignition component and the oil a bad stem seal on the intakes.
Good thought on a leak down test. I'll see about getting a tool kit.
 

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weak blinking on that side looks like the hall pickup is failing on that side -
run through the troubleshooting chart..

Rayman
 

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Discussion Starter #15
weak blinking on that side looks like the hall pickup is failing on that side -
run through the troubleshooting chart..

Rayman
Perfect! Thanks Rayman! Will report back in the next day or two
 

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weak blinking on that side looks like the hall pickup is failing on that side -
run through the troubleshooting chart..

Rayman
Rayman
Just curious if you are seeing more of this? Helped Luke here with a bad hall plate unit. never heard if you did FA on it's return?
 

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There have been a small proportion of hall units that have failed over time with use - Ive traced it to stress on the Surface mount components due to thermal cycling - the expansion and contraction of board / components and epoxy can all cause fracturing of the SMT joints - there are two where it seems to occur -
Why it occurs on some bikes and not others - can be down to usage pattern / environment / oil level or phase of the moon -

As a result there is a newer version of the hall plate that I now ship as standard that has only Though hole components.
For those users that encounter a failure - I replace with the new pickup when the need arises, for shipping costs only - whether in or out of warranty period.

Regards
Rayman
 

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Discussion Starter #19
Just tried the new GY6 boxes from murray. No different. Still a weak flashing light. Looks like there is something wrong with that pick up. Going to try to go through the rae-san troubleshoot chart this evening.
 

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Discussion Starter #20
There have been a small proportion of hall units that have failed over time with use - Ive traced it to stress on the Surface mount components due to thermal cycling - the expansion and contraction of board / components and epoxy can all cause fracturing of the SMT joints - there are two where it seems to occur -
Why it occurs on some bikes and not others - can be down to usage pattern / environment / oil level or phase of the moon -

As a result there is a newer version of the hall plate that I now ship as standard that has only Though hole components.
For those users that encounter a failure - I replace with the new pickup when the need arises, for shipping costs only - whether in or out of warranty period.

Regards
Rayman
Here is a video of a discovery I made while going through the ignition troubleshooting pdf. I made it all the way to "One set flashing" before I ran into the issue in the video. When I touch or move the White/Red wires coming out of the unit, the bike dies. Did I wire something funky or put the wires to close together? The connectors seem fine. Hope the video is useful. Let me know if I need to pull the back cover Rayman.

 
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