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I still want to find out what the white/red wire does.
So far, the only thing that makes sense to me about this red/white wire, is that it places maximum retard on the spark advance for the easiest motor spin for starting. Notice the only time there is a signal on the wire, is when you have the start button pressed.
 
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Ok, time to get scientific!
Using my lunch break and my work's FLIR camera, I took an infrared video of my bike during a 6:30 minute cool down.
You sure have access to some cool tech.
I was thinking that the carbs are fairly well insulated from heat sink of the engine due to the rubber mounts. I suppose there could be some ambient heat absorption from the engine, but not sure there would be enough to affect internal bowl pressures; especially with proper venting.
 

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So far, the only thing that makes sense to me about this red/white wire, is that it places maximum retard on the spark advance for the easiest motor spin for starting. Notice the only time there is a signal on the wire, is when you have the start button pressed.
Yep, that's what I'm thinking.
 

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The only thing that I have observed to be consistent with this issue is the obvious part and that is the bike is hot. Sometimes opening the throttle works, sometimes not, sometimes the choke helps, sometimes not and sometimes the bike starts hot with the slightest touch of the start button. Thankfully it always starts though. I’d love to figure this one out.
 

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I don't know how long this board has been in existence, but I would guess early January of '04. That's about the time the first post about hard hot starting shows up. This issue has haunted the board for years. If you read a bit of the verses and posts, you find the most consistent answer to the hard hot starting issue (and heart attacks from surprise backfires), is to replace the battery with maintenance free (AGM), and to 'set' the pickup coil gaps to .020". Full disclosure, these two things are what I think fixed my ride as well.
I do believe it is an electrical issue, and I think it is a slight mismatch of the pickup coils and igniter front end engineering. I think under hot conditions, the magneto flux and pickup coils response are both weakened to the threshold of the peak detectors that necessarily must be present in the discrete circuitry of the igniter module. The reduced sag of the AGM battery, and the increased pulse amplitude generated by the coils being closer to the passing magneto, provide the margin of safety to ensure trigger detection. That is my theory, but I have no test designed to prove it. Just thought I'd throw that out there for consideration.
 

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Discussion Starter #46
I don't know how long this board has been in existence, but I would guess early January of '04. That's about the time the first post about hard hot starting shows up. This issue has haunted the board for years. If you read a bit of the verses and posts, you find the most consistent answer to the hard hot starting issue (and heart attacks from surprise backfires), is to replace the battery with maintenance free (AGM), and to 'set' the pickup coil gaps to .020". Full disclosure, these two things are what I think fixed my ride as well.
I do believe it is an electrical issue, and I think it is a slight mismatch of the pickup coils and igniter front end engineering. I think under hot conditions, the magneto flux and pickup coils response are both weakened to the threshold of the peak detectors that necessarily must be present in the discrete circuitry of the igniter module. The reduced sag of the AGM battery, and the increased pulse amplitude generated by the coils being closer to the passing magneto, provide the margin of safety to ensure trigger detection. That is my theory, but I have no test designed to prove it. Just thought I'd throw that out there for consideration.
I've been thinking about this for a few years now. My previous bike never really showed any hot-start issues. Though I did the coil pickup mod on it fairly early into owning it. The ignition pickup mod is easy enough to do. Done properly, it's possible to revert back to stock gap (for purpose of comparison). It's a plausible cause, and doesn't hurt anything. I just don't want to change 3 things, have the issue fixed, and not know which thing fixed it.

My new bike really doesn't like hot starts. I tried the direct coil mod on my new bike with no perceivable change. I also have iridium spark plugs with no perceivable change. Neither bike had an an AGM battery, but the battery on this bike is much stronger than the old bike battery ever was.

I'd like to not only eliminate the issue, but be able to prove the cause of the issue. I'm still suspecting fuel issues, as my latest experiments seemed to suggest. A backfire sounds like it still is sparking.

I did find some general information relating to ignition systems.
"The greater the in-cylinder pressure, the harder it is for an electric current to travel through the fuel/air mixture between spark plug electrodes, raising voltage requirements accordingly."
"Finally as the air/fuel ratio becomes leaner, the voltage required to produce a spark becomes even higher. "

Going WOT to start would increase the in-cylinder pressure, and lean out the mixture. Both of these would require more voltage to spark. Some have had success with adding choke, which would lower the voltage requirements. Now, going WOT would make the engine spin a little bit easier, putting less load on the starter/battery, giving more battery voltage. So even with this, it's not clear.

I'd be curious if anyone else having hot start issues is able to repeat my observations. Shut off the fuel prior to stopping, and see if it helps the hot start issue.
 

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FREEBIRDS MC CENTRAL NY
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This thread is way beyond my comprehensive skills and now my brain hurts. Big words. Big words.

Sent from my A501DL using Tapatalk
 

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FREEBIRDS MC CENTRAL NY
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AGM battery cured it on Melissa Fayhe

Sent from my A501DL using Tapatalk
 
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