Got a used '85 nighthawk and finally got it running.....enough to see some blue smoke from the exhaust. Bike needs usual maintenance items but how much do I want to put into the bike considering the smoking problem?
The engine sounds good while running (still could use a little carb cleaning) but the smoke concerns me. Is this common on Nighthawks?
As long as I keep an eye on the oil, is it even anything to worry about?
Blue smoke
- BuzZz
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Blue smoke is probably oil smoke, as you figured. Now, how long did you run the bike once you got it fired up? Did you ride it? I'm wondering only because if you just fired it up, seen the smoke and didn't ride the bike, the oil smoke could have just been oil build-up in the cylinders from sitting and could clear up with a few miles.
If you did ride it and the smoke persists, then you probably have worn rings/scored cylinders/leaking valve stem seals. That can be overlooked if it is not too bad, and you keep an eye on your oil level, like you're thinking. If your using a liter oil oil every 100 miles or something, then you might want to consider a rebuild if you plan on keeping the bike and sinking a bunch of money into it.
It all depends on the severity and your personal comfort level with the situation.
If you did ride it and the smoke persists, then you probably have worn rings/scored cylinders/leaking valve stem seals. That can be overlooked if it is not too bad, and you keep an eye on your oil level, like you're thinking. If your using a liter oil oil every 100 miles or something, then you might want to consider a rebuild if you plan on keeping the bike and sinking a bunch of money into it.
It all depends on the severity and your personal comfort level with the situation.
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- Johnj
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It's an 85, how much resale did you want? Like Buzz said it might just be from sitting around for a while and may clear up after putting a some miles on it. If it only smokes for a while after you start it the engine most likely needs valve guides. If it continues to smoke all the time it's to be the rings.
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Always wear a helmet, eye protection, and protective clothing. Never ride under the influence of drugs or alcohol.