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Discussion Starter · #1 ·
Hi everyone,

I had been working on an 86 VT700 with 1800 miles and sitting in a garage for several years. I did the carb cleaning (all new jets and float valve), oil, coolant, sparks plugs, air and fuel filter. The bike is running nicely and I finally had a short ride (quarter mile or so) today. I see white smoke (steam?) coming out from the exhaust. (I think it is white. But I hope not. Maybe burning a little extra oil? Or bad fuel/air mixture? Really dont know.) (by the way is there an air/fuel mix adjustment on this bike?)
Checked the spark plugs: there were kind of covered in dark smoke and smelled like fresh fuel.

BUT here is the main flag: after the short ride I saw minor coolant leaking from around a large bolt and with wire attached on top by a small screw just next to the water pump. I understand it is a switch but not sure for what. I saw a little water residue around the bolt after I removed the plastic cover. I opened the small screw holding the wire. There is an opening through the bolt. But I did not touch the bolt (I think it is 19mm).

I highly doubt I have a head gasket issue. Perhaps a blocked cooling system (thermostat or water pump)? But where I flushed the coolant it came out nicely. By the way the temperature never rose that much for the fan to kick in. (It is cold now in New York.) Also, do I need to worry too much about the coolant I am using? It is a 50/50 mix. Thanks for your help. I will try to post a pic of the bolt I am talking about if that helps.
 

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Water vapor is a by-product of burning gas. Under the right conditions white vapor out the tail pipe is normal and seen more in cooler weather. That said a blown head gasket can also do this. A short drive will not be enough to know one way or the other.
 

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I don't know about a bike, but white smoke is steam and both times my car did that after it had warming up it was a head gasket. The only time I had a bike blow a head gasket I had fire shooting out the side of the engine, not a pretty sight.
 

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Post some pics of your plugs. They should tell the tale. As far as the A/F screws, should be removed to clean them then initially set @ 2 1/2 turns out.
 

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Discussion Starter · #5 ·
Post some pics of your plugs. They should tell the tale.
OK I will. Since they plugs were in when I still had carb problems (blocked jets) and now the carb is fine, I will clean the plugs nicely, run the bike for a while and then take pics. That way we know what's happening.
 

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Discussion Starter · #6 ·
Leak_zpse0a0a4e4.jpg Photo by QuantumTime | Photobucket
Plugs_zpsd2849397.jpg Photo by QuantumTime | Photobucket

The first link above shows the bolt where I got the coolant leak from. It is located under the engine adjacent to the water pump and oil filter. There is switch screwed on top of the bolt. I had removed the rubber cover to the pic.

The second link shows the plugs after I ran the engine (not driving, bike on the center jack) for about 15 minutes. The only one that looked a bit dirty was the Right Front one. But even that was not so bad. Lots of white smoke was coming out from the exhaust. But the weather was also cold. The engine temperature had risen to a bit more than half but I dont think the fan had come on. I didn't see a sign of blown head gasket. I will check the coolant level tomorrow to see if it has gone done. I highly doubt if the steam from the exhaust is the coolant. Hopefully not!
 

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Not familiar with your particular bike, but that's not a bolt. I believe it's your oil pressure sending unit judging by the location. And yes, those are definitely spark plugs. Any chance we might get a closer peek at the business end of things? Hard to see without my binoculars. J/K! Also, forgot to ask. Are you running seafoam or any other gas additive right now?
 

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Hi everyone,

I had been working on an 86 VT700 with 1800 miles and sitting in a garage for several years. I did the carb cleaning (all new jets and float valve), oil, coolant, sparks plugs, air and fuel filter. The bike is running nicely and I finally had a short ride (quarter mile or so) today. I see white smoke (steam?) coming out from the exhaust. (I think it is white. But I hope not. Maybe burning a little extra oil? Or bad fuel/air mixture? Really dont know.) (by the way is there an air/fuel mix adjustment on this bike?)
Checked the spark plugs: there were kind of covered in dark smoke and smelled like fresh fuel.

BUT here is the main flag: after the short ride I saw minor coolant leaking from around a large bolt and with wire attached on top by a small screw just next to the water pump. I understand it is a switch but not sure for what. I saw a little water residue around the bolt after I removed the plastic cover. I opened the small screw holding the wire. There is an opening through the bolt. But I did not touch the bolt (I think it is 19mm).

I highly doubt I have a head gasket issue. Perhaps a blocked cooling system (thermostat or water pump)? But where I flushed the coolant it came out nicely. By the way the temperature never rose that much for the fan to kick in. (It is cold now in New York.) Also, do I need to worry too much about the coolant I am using? It is a 50/50 mix. Thanks for your help. I will try to post a pic of the bolt I am talking about if that helps.
Cold weather startup will result with exhaust vapor as the engine warms up, just like cars. As for the minor coolant leak you might just need to snug up the bolts because of the temp drop. If you're worried about coolant contamination in the oil, remove the oil dipstick it should look like oil and not milky white.
 

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The black plastic object between the oil filter and water pump with the wire attached is the oil pressure switch. The water pump is just forward of that switch. At the bottom of the water pump is a weep hole for coolant to exit if there is a seal failure. Look closely there. If that's the source of the water, it's blowing back onto the switch when you ride. If it's the source of the water, it may be time for a new pump. I'd want to verify it isn't a leak from the the flange seal where it bolts to the engine, or a loose hose clamp etc... before I spent the money on the pump. Sidenote: My brother had the same problem on his bike. It dripped a few drops each time he rode but he just watched it and let it go. It was never enough to cause a problem so he left it like that for a couple of years. He gave the bike to me and I replaced the pump just because I didn't like the leak although I didn't really have to.
 

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Cold weather startup will result with exhaust vapor as the engine warms up, just like cars. As for the minor coolant leak you might just need to snug up the bolts because of the temp drop. If you're worried about coolant contamination in the oil, remove the oil dipstick it should look like oil and not milky white.
Many years ago, a brother-in-law had a car which did that. He thought the car had a crack or blown gasket so he gave it to me. I was just a kid and didn't know better. I talked to people and found out about that. I kept the car for quite a while. There was really nothing wrong with it.
 

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An 86 with only 1800 on it, how long did it sit without being driven? I would assume a long time, long enough for gaskets and seals to dry out. If you don't have a major leak I would put a few miles on the bike before i did anything to it. It's quite possible things will clear up.
 

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Discussion Starter · #14 ·
Sometimes coolant gives off a sweet smell out of the exhaust.
Yes, someone told me the same thing. I dont think I smell any sweet so most probably it is really nothing but just the cold air effect. I really have to drive the bike to see how it acts. May this weekend when it is a bit warmer around here.
 

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Discussion Starter · #15 ·
An 86 with only 1800 on it, how long did it sit without being driven? I would assume a long time, long enough for gaskets and seals to dry out. If you don't have a major leak I would put a few miles on the bike before i did anything to it. It's quite possible things will clear up.
I agree with you; I think it is just some very dried out gasket and driving the bike will bring them to life. The leak is not serious. In fact when you run the engine without driving there is no leak. So it might go away. I will drive the bike for a longer time this weekend and see what happens. Apparently the bike was sitting for 5-6 years and before that it was used very rarely. That's why it looked so damn good!
 

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Discussion Starter · #16 ·
Ok, I think it is time to bring a closure to this thread, and it is a good one: the white smoke was being produced by contaminated gas. Apparently I had inadvertently mixed some of the anti-rust stuff I had used to clean and flush the gas tank with some fresh gas and then poured it in the bike. Anyway, I flushed the tank and the reserve again today and poured in fresh 89 gas and no white smoke. I think my bike is finally in perfect condition so all I can ask for now is some unusually nice weather here in New York so I can ride. Otherwise will wait till spring for a real ride.
 

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Glad to hear you finally got it figured out. Ride safe!
 

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Glad it was a mistake that was finally discovered and easily corrected. :D
 
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