Exhaust Burn-Off - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 6 (permalink) Old 06-19-2008, 10:26 AM Thread Starter
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Exhaust Burn-Off

I will through this question out for everyone. A little backround on the bike, it is a 92 Vulcan 750 with 1800 miles. I picked this bike up last weekend from an old couple who had not ridin the bike in over 5 years. The bike was not running and I got a killer deal. I replaced all fluids, and took the carbs out of the bike and cracked them open and cleaned. The bike runs like a top, lots of power for a smaller bike. My question is about some burning on the rear exhuast manifold. This is not a smoke like white (Coolant) or Blue (Oil) it is like a burning plastic consistancy. Is this simply the exhaust manifold burning off some rust or residue from sitting so long. I haven't had a chance to ride for a long period of time or to see if the burning stops, I just wanted to see what you fellas thought, I don't want it to catch on fire or miss something that the problem could be....
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post #2 of 6 (permalink) Old 06-19-2008, 10:35 AM
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My best guess would be 1 of 2 things - a sealant of some type was used and is burning off - or someone's raingear/ pants got flopped into the area in question and is burning off.

Only other thing I can think of is bad... burning wires...

Take the bike for a 100 mile ride once you feel it's reliable (though with smoke happening if you really are concerned about it it wouldn't be a bad idea to carry a fire extinguisher with ya... heck, it's a good idea period but most of us, myself included, dont)... many times mechanical things will in fact smell a little funky after sitting for too long...

Curtis - Albany Oregon.
Currently receiving therapy from "Doc" - My 1985 VN700.

Daily rider in NorthWET Oregon.
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Bought Feb 2007 with 12K miles.
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post #3 of 6 (permalink) Old 06-19-2008, 12:16 PM Thread Starter
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I've checked pretty close for wires burning, but that is not it, it is definitly coming from the exhaust manifold. I fell the same as you do about the 100miile ride and the fire ex. I really don't want to catch on fire..... Hopefully what ever it is will burn-off and stop smoking.
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post #4 of 6 (permalink) Old 06-19-2008, 12:26 PM
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On the long ride I would stop ever so often and check the pipe and see if you can see where the burning is coming from. If it starts to discolor I would say that something had a long time ago stuck to the pipe when it was hot. As the pipe gets really hot the substance will burn off, but will leave a discolored spot on the pipe. On an old bike of mine I did it with plastic, when I coved the bike before it was cool enough. It left a black spot on the pipe after it burnt off. LOL and ride safe.

2004 25,500 miles
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post #5 of 6 (permalink) Old 06-19-2008, 01:52 PM
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Any idea if the old couple had any work done to the pipes?
Might be some type of exhaust gasket that hasn't really got seated in (or burned in, in this case) as Curtis mentioned

AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC

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post #6 of 6 (permalink) Old 06-19-2008, 09:39 PM
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There are two plastic spacers on the rear exhaust manifold that are part of the engine mount there. It is possible that one of them has deteriorated to the point of now melting. Normally, the plastic is up to the task of taking the heat. Or it could be that one of these spacers was replaced with something non standard and it is melting as a result. They aren't hard to replace and an engine pull is NOT required. If this is the problem, you'll just have to remove the long bolt that is the engine mount, remove the spacers, replace them and rebolt the thing together. Shouldn't take longer than 10-15 minutes.

Jim W
93 VN 750 "Ursula"
Moved R/R 08Sep06
R/R rewire 17Feb07
New R/R, Installed 14Jun08
New Stator installed 10 Jun08
Maintenance Free Battery 12Jan08
21480 Miles
VROC #8542
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