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Discussion Starter #1
Hey all,

This time last year and this year, when the weather changed to a little bit cooler, I started experiencing really rough cranking and idling. I am fouling plugs as well and it backfires alot. When it is warm, I have no problems cranking or idling or fouling plugs.

My bike is a 1999 California Motorcycle Company softail custom with an S&S 88 inch motor. I bought it in July of 2010. It has a Thunderheart ignition with a dual fire coil. As far as I know, everything is original as it has very low miles, 7500 miles. I was wondering if my coil could be going bad or maybe something else in the ignition system. I am at a loss and am open to any suggestions. The bike runs extremely well in warm weather, especially after I put the RB Racing pipes on it. Oh yeah, a plug change will generally straighten it out for a bit. Any ideas?

Thanks.
 

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Hey all,

This time last year and this year, when the weather changed to a little bit cooler, I started experiencing really rough cranking and idling. I am fouling plugs as well and it backfires alot. When it is warm, I have no problems cranking or idling or fouling plugs.

My bike is a 1999 California Motorcycle Company softail custom with an S&S 88 inch motor. I bought it in July of 2010. It has a Thunderheart ignition with a dual fire coil. As far as I know, everything is original as it has very low miles, 7500 miles. I was wondering if my coil could be going bad or maybe something else in the ignition system. I am at a loss and am open to any suggestions. The bike runs extremely well in warm weather, especially after I put the RB Racing pipes on it. Oh yeah, a plug change will generally straighten it out for a bit. Any ideas?

Thanks.
I'm no expert on this but it sounds like this might be self induced. To my knowledge the weather hasn't been that cold to need alot of chock on startup, as soon as it fires you should be able to back the chock almost completely off and only use just a bit of chock for a minute or two before you're ready to go. Sounds to me like you're fouling you're plugs by using too much chock and then it just goes down hill from there
 

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Discussion Starter #3
enrichener

Pigrider,

Thanks for the feedback. I have an enrichener on the Super E that I do not use.

It seems that this only happens when it gets cooler. I was hoping someone would point toward the coil going bad or operating intermittently, until the whole engine area heats up.

Thanks.
 

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Pigrider,

Thanks for the feedback. I have an enrichener on the Super E that I do not use.

It seems that this only happens when it gets cooler. I was hoping someone would point toward the coil going bad or operating intermittently, until the whole engine area heats up.

Thanks.
My experiance with coils is that they usually go bad when they get hot, not cold. I know there's a test you can do on you're coils with a muti meter but you'd need to get the specific info for you're coils to get the right numbers that you're looking for. You might try running next step hotter plugs and see if that helps.
 

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Discussion Starter #5
hotter plugs

My experiance with coils is that they usually go bad when they get hot, not cold. I know there's a test you can do on you're coils with a muti meter but you'd need to get the specific info for you're coils to get the right numbers that you're looking for. You might try running next step hotter plugs and see if that helps.
Hotter plugs seemed to help a bit. Now, I am running Autolite AP65 plugs. I cannot get over how clean they look. It makes me think I might have timing issues or too much advance.
 

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Discussion Starter #6
hotter plugs

Pigrider,

Thanks to your recommendation, I must be onto something. I have put a couple hundred miles on the bike since changing to the hotter plugs and it isn't beginning to hint at trying to foul them. The color looks good, too. It is amazing how much heat range of plugs affects performance on the air-cooled V twins. This is much different than my experience with automobiles.

Thanks, again.
 

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Pigrider is right, choke is last resort specifically for that reason, you are overriding that condition with the hotter plug.

Choke = less air = dirty burn = fouled plug

Hotter plug = better burn with limited air will smoke w/choke!

My 2 cent
 

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Discussion Starter #8
I must be missing something

Pigrider is right, choke is last resort specifically for that reason, you are overriding that condition with the hotter plug.

Choke = less air = dirty burn = fouled plug

Hotter plug = better burn with limited air will smoke w/choke!

My 2 cent
I am not following any of this. I do not use the choke as I do not have one. I have an en-richener that I do not use as well. I do not want to make the rich condition worse.

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Did not realize the en-richener was in place of a choke, that is where you lost me.

Heat excites atoms and causes them to occupy more volume in space. So there for, the hotter your air is, the thinner it is.

Your air flow is slightly minimized in the cooler weather due increased density.

Have a nice day
 

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It could be that you're engine is tuned/jetted on the edge of being too rich. This is not a bad thing in the hot summer months especially if you do alot of riding and are getting you're engine good and hot, a little extra fuel will tend to cool it some. However when the weather cools off you're engine will not run as hot which will create a rich condition. If you're bike is running good other than this problem I'd just put the hotter plugs in for cooler weather and see how they're burning come next spring, you may have to put the cooler plugs back in for the summer but the hotter plugs may be what you need year around. When you start making modifications to intake, exhaust, ignition, you kinda have to play it by ear for you're specific bike. I've never messed with carb jets that much but I do know that there is no set rule for what # jets to use, people can give you a ballpark # that will get you close but you still need to fine tune from there.
 
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