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Discussion Starter #1
I apologize if my search-fu is weak: I looked around and couldn’t find an answer.

I recently replaced the battery in my bike after (stupidly) letting it sit and discharge all winter. After getting a new battery installed I started it up to make sure everything was good. A minute or 2 later I noticed thin wisps of whitish smoke/vapor coming up from under the frame in front of the battery box, right around where the rear of the tank bolts down, possibly from the rear cylinder. I shut everything down to prevent damage, grabbed a flashlight and looked around but couldn’t find the source of the smoke/vapor. Everything's packed so tight in there it's hard to see. I removed the battery and made sure the battery box was clean, then reinstalled the battery. I started the bike again to see if this was a one-time occurrence; it wasn’t. The bike still smokes and I can’t for the life of me figure out why. I know the battery box is clear, so nothing's melting or burning there.

Also, I noticed some wet-spots on the concrete at the end of the pipes, but figured it was probably just condensate from inside the pipes since it was around 40* in my shop. I moved the bike to another spot and started it again: more water spots and smoke/vapor. I dabbed some of the liquid and it didn’t smell like antifreeze so I don’t think I have a coolant leak, but I don’t know what else it could be. It certainly didn’t smell like gas.

What really bothers me is that about 2 months ago I jump-started the bike (thus learning I needed a new battery) and it didn’t smoke or drip at all, even after running for about 30 minutes.

I readily admit that I am not much of a mechanic, and if this isn’t something I can fix at home my bike will go to the local dealer for repair. But I'd like to save that money if possibly, so I turn to the community here for help and advice. What’s going on here, and is it something I can fix myself?

Thanks.
 

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Have you let it warm up enough to quit smoking?I tend to think your rear carb is leaking fuel into the rear cylinder while sitting for an extended period and smoking around your exhaust,exhaust leak? The spots on the floor indicate some kind of leak.I would look it over good to see if I could find where it is coming from ,even if you have to remove the tank.

Or does it smell like wires burning?
 

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Discussion Starter #3
I have not let it warm up enough to stop smoking, no. I was afraid to let it continue running for fear of causing damage. The smoke/vapor is odorless, and nothing that I could see looked burnt/melted.

I had the carbs pulled apart and rebuilt last spring due to plugged jets, so I'd think the carbs wouldnt be leaking unless that's simply a common, typical thing.

I'll try again tonight to see if I can spot where this smoke/vapor is coming from. Thanks.
 

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no clue on the fluid other than condensation. I would look to make sure the plastic sleeving on the bullet connectors from the stator are not overheating....mine did that once and it did look like whisps of smoke.

The 3 yellow stator wires coming from the left side or the engine cover have bullet connectors located in front of the battery box (mine were routed just behind the rear cylinder exhaust port) and should NOT be bundled together as they get pretty warm. if they are bunched together they tend to melt the plastic around them and could short out.

Just something to look for....just in case. :smiley_th
 

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Check the connectors per the previous post. The factory ones on my 750 smoked too. The contacts were blackened under the plastic. After replacing the connectors entirely, The bike ran better, the battery stayed charged, and she started with a slight touch of the starter button.
The wires are the three yellow wires from the stator on the left side of the engine. The connectors will be under the left side cover. Hope it's nothing more than that!
Bronson
 

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Discussion Starter #6
Thank you both for your answers; I really appreciate the advice.

@ KC, after running the bike Wed. night trying to trace the source of the smoke I noticed that there were no water spots on the floor, so I can only surmise that it was in fact condensation from the cold air earlier this month.

@ KC & Bronson, I looked at the connectors on the stator wires last night and, while they got fairly warm, they never started smoking. Incidentally, I couldn’t see smoke anywhere at all, even after riding into/around town and then back home, about a 6-mile round trip. It's just stopped. I wish I understood why so that my mind would be at ease (I’m paranoid and a cynic), but for the moment I’m not going to look the gift horse in the mouth. I’m just happy I can ride again.

I won’t say the issue has been resolved, because I do not know what was causing the smoke or why it suddenly stopped. So, I’m going to be keeping an eye on things to see if it does this again. If it does, it’s off to the shop for repair. If not, well, I guess I’m just lucky.

Thanks again for your input folks. I’m glad to be part of such a helpful community. :)
 

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Thank you both for your answers; I really appreciate the advice.

@ KC, after running the bike Wed. night trying to trace the source of the smoke I noticed that there were no water spots on the floor, so I can only surmise that it was in fact condensation from the cold air earlier this month.

@ KC & Bronson, I looked at the connectors on the stator wires last night and, while they got fairly warm, they never started smoking. Incidentally, I couldn’t see smoke anywhere at all, even after riding into/around town and then back home, about a 6-mile round trip. It's just stopped. I wish I understood why so that my mind would be at ease (I’m paranoid and a cynic), but for the moment I’m not going to look the gift horse in the mouth. I’m just happy I can ride again.

I won’t say the issue has been resolved, because I do not know what was causing the smoke or why it suddenly stopped. So, I’m going to be keeping an eye on things to see if it does this again. If it does, it’s off to the shop for repair. If not, well, I guess I’m just lucky.

Thanks again for your input folks. I’m glad to be part of such a helpful community. :)
Hey if it ain't broke,don't fix it.Mine actually did the same thing once or twice on a cold start the rear cylinder would flood a little and smoked like that until it warmed up,keep your eyes peeled and like you said ,don't look a gift horse in the mouth.:)
 

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As I read about the smoke in the beginning lines of the OP I was sure this was going to be electrical wires burning off insulation, because I had the smoking wires once. :(

I think I was trying to start the bike the summer after my accident. The regular wet cell battery that came with the bike wouldn`t crank the starter over, so I was going to boost it with a car battery. The wiring harness bundle wrapped up with tape started to smoke just behind the tank a few seconds after I hooked up the jumper cables. I quickly removed the jumper cable and the smoking quit. I unwrapped the tape so I could examine the wires, but didn`t find any that looked burned, just one that had melted a bit IIRC.

I have started the engine several times since then with my new MF-AGM battery, and have not had any problems or a recurrence of smoking wires. All fingers crossed here that it doesn`t reoccur when I go for my first ride since the accident in 2008.

Hopefully that ride will be in the next few weeks!!
:lockd::pepper::lockd::pepper::lockd::pepper:

You all will hear about the ride here whether it is successful, or goes up in smoke. :wow:
 

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Odorless white smoke=steam, ie condensation (hopefully not coolant leaking into the engine).
A pungent white smoke, almost always=wiring.
Oil smokes blue.
Gas in an overrich engine smokes black.

As was said by others, the wires from the stator and pickup coils can smoke, and yes, they do get hot. I replaced my Pickup wires (3 yellow) with heavier gauge from engine to harness.

Check your coolant for any oil as well....and oil for milkyness...
 
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