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Discussion Starter · #1 ·
Here's my link from the old forum: Archived Post



Here's where I am so far:

  • Gas tank vent - Fine.
  • Fuel line - Fine.
  • Vacuum for Petcock - Fine.
  • Carburetors - Rebuilt but could use Larry-ization.
  • Spark Plugs - Fine.
  • Spark Plug Caps - Fine.
  • Spark Plug Wires - Fine.
  • Coils - Fine.
  • Ignition Modules - Fine.
  • Pulse Generators - Fine.
  • All wiring for ignition circuit - Fine.
This morning, I finally got myself out to the garage and checked EVERYTHING! Everything checks out just fine. Bike still dies when it warms up. I'm going to replace the thermostat as it appears to be sticking so the bike is running hotter than normal. I'll also check the fan circuit. I will then use the 6' fuel hose and vacuum line I bought to set the tank on my work bench and run the bike with the tank off. I will then check each component as it warms up to see where I'm losing power.



As I run the bike, the plugs have BRIGHT blue spark. When I run it till it's hot, one side dies, then the other. THE PLUGS ARE NO LONGER SPARKING! Once it cools down, they work fine again. This is driving me nucking futs!
 

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Here's my link from the old forum: Archived Post



Here's where I am so far:

  • Gas tank vent - Fine.
  • Fuel line - Fine.
  • Vacuum for Petcock - Fine.
  • Carburetors - Rebuilt but could use Larry-ization.
  • Spark Plugs - Fine.
  • Spark Plug Caps - Fine.
  • Spark Plug Wires - Fine.
  • Coils - Fine.
  • Ignition Modules - Fine.
  • Pulse Generators - Fine.
  • All wiring for ignition circuit - Fine.
This morning, I finally got myself out to the garage and checked EVERYTHING! Everything checks out just fine. Bike still dies when it warms up. I'm going to replace the thermostat as it appears to be sticking so the bike is running hotter than normal. I'll also check the fan circuit. I will then use the 6' fuel hose and vacuum line I bought to set the tank on my work bench and run the bike with the tank off. I will then check each component as it warms up to see where I'm losing power.



As I run the bike, the plugs have BRIGHT blue spark. When I run it till it's hot, one side dies, then the other. THE PLUGS ARE NO LONGER SPARKING! Once it cools down, they work fine again. This is driving me nucking futs!


Just a thought... My GL650 ran great when cold, but starting missing and dieing once it warmed up until I removed the resistors in the plug caps and replaced them with brass rod- problem magically dissapeared. Just a thought. I chased the same things you are chasing for months... I think maybe in the same order listed too.
 

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Unfortunately there's no way to test a faulty coil that may be breaking down with heat except to swap it with a known good one.This may be the cause.Also if the Air-dam is missing this can also cause the symptoms.
 

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Discussion Starter · #4 ·
Just a thought... My GL650 ran great when cold, but starting missing and dieing once it warmed up until I removed the resistors in the plug caps and replaced them with brass rod- problem magically dissapeared. Just a thought. I chased the same things you are chasing for months... I think maybe in the same order listed too.


Resistors are out of the picture. I replaced the spark plug wires and boots with 7mm solid core wires and automotive boots to keep the wires away from the heads. Thanks though!
 

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Discussion Starter · #5 ·
Unfortunately there's no way to test a faulty coil that may be breaking down with heat except to swap it with a known good one.This may be the cause.Also if the Air-dam is missing this can also cause the symptoms.


Thought that myself as I had one do it before. I don't have a spare though. And what do you mean by air-dam?
 

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Hi,

Have you tried a resistance check on the blue/yellow wires to the pulsars ? Do a check cold , then try again when hot, the windings may be shorting with heat exspansion.
 

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Discussion Starter · #10 ·
Hi,

Have you tried a resistance check on the blue/yellow wires to the pulsars ? Do a check cold , then try again when hot, the windings may be shorting with heat exspansion.




Yep, both pulsars show 520 ohms. I still have to check them when it gets hot. I just purchased 6' of fuel line and vacuum line so I can run the bike with the tank off. This will allow me to check the coils as well when it gets hot.
 

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ok heres just a thought what about the main fuse i recall a few people on the old forum had this problem bike runs great cold but when warm it dies so if you think about it the metal in the fuse is shrinking when the bike is hot and when its cold it goes back to normal so i think there might be a hair line crack in the fuse try to replace that and report back your findings and if this has already been covered then forget what i said....
 

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Discussion Starter · #12 ·
ok heres just a thought what about the main fuse i recall a few people on the old forum had this problem bike runs great cold but when warm it dies so if you think about it the metal in the fuse is shrinking when the bike is hot and when its cold it goes back to normal so i think there might be a hair line crack in the fuse try to replace that and report back your findings and if this has already been covered then forget what i said....


Good idea lucky, but no
Someone had suggested it before. I took the fuse out and cleaned it and the contacts up real nice. Definitely not failing there.
 

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Discussion Starter · #14 ·
Have you made sure the fuel cap vent is clear?


Nigh impossible to clog the vent on these CX650s Shep. The rubber gasket on the cap is ribbed to allow airflow around it's entire circumference. I did remove it already and make sure there wasn't spiderwebs or something else that might block it. Thanks though!
 

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Nigh impossible to clog the vent on these CX650s Shep. The rubber gasket on the cap is ribbed to allow airflow around it's entire circumference. I did remove it already and make sure there wasn't spiderwebs or something else that might block it. Thanks though!


Much better design than the stock CX then.I opened the hole out on both mine as they are tiny and easily clogged and high pressure air blow them through from time to time.



I'd still replace the main fuse holder even if it looks good and here's why,





http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=8&t=27
 

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Discussion Starter · #16 ·
Okay, going out on a limb here... I just ordered 2 brand new ignition coils that fit a 1980 Fiat X1/9. They were only $12 each. I'm going to wire them in and see how she holds up. If she runs while hot, that was the problem. If she still dies, I guess I'll shoot myself.



Seriously, it will mean more testing. I figured new coils to replace 27 year old ones won't hurt.
 

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Okay, going out on a limb here... I just ordered 2 brand new ignition coils that fit a 1980 Fiat X1/9. They were only $12 each. I'm going to wire them in and see how she holds up. If she runs while hot, that was the problem. If she still dies, I guess I'll shoot myself.



Seriously, it will mean more testing. I figured new coils to replace 27 year old ones won't hurt.


My sentiments exactly.As per my link I had no end of trouble tracking down the intermittent fault on the left hand side of one of my CX last year when raining which led to me finding cheap alternative CDI coils which of course you can't use hence the Car ones




But don't forget that even one bad plug cap can cause no end of problems dumping all the power of the bike in certain circumstances.
 

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Discussion Starter · #18 ·
My sentiments exactly.As per my link I had no end of trouble tracking down the intermittent fault on the left hand side of one of my CX last year when raining which led to me finding cheap alternative CDI coils which of course you can't use hence the Car ones




But don't forget that even one bad plug cap can cause no end of problems dumping all the power of the bike in certain circumstances.




Plug caps are long gone. Didn't want the headache so I removed them. Wires go straight to the plugs now with insulators I got off a Chevy Lumina to keep them from touching the heads and valve covers.



All I could find for coils were used or NOS so I figured what the hey. Now I'll just have to figure out how to mount them!
 

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Wish I had seen this sooner, I would have let you borrow a set of 650c coils for testing/troubleshooting purposes...
 
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