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Discussion Starter #1
The Nighthawk doesn’t get ridden much, so I’ve decided that it needs a Battery Tender on it. It does have a little Stabil added to the tank because I know it sits. Before I got to the install, I got up the nerve to take my 5-yo for his first ride on the road. I had him get into his racing leathers while I pulled the bike out of the garage.

I turned on the choke and thumbed the start button and it turned over like a fresh battery should. But it wouldn’t start. Doh! Forgot to turn on the fuel selector, carbureted bike.

Did that and thumbed the starter again while I played with the choke setting to get it to catch. I noticed that it was dripping fuel from all 4 carbs like a sieve even while running. I turned off the fuel valve thinking maybe the floats were full from my failed start creating high vacuum. It continued to run. I let the bike warm in the OFF position and the dripping slowed. Turning the knob to RES also gave a fuel loss. But turning it off gave just a slow drip.

I decided (I hoped) we weren’t going to be the subject of a “never again” story with a bike catching fire as it seemed standing the bike vertical had a positive effect.

I turned on the fuel and away we went. I took a glance a couple times enroute and it seemed cured. About 20 minutes of running the bike through various speeds, gears, loads and RPM we returned with a lot of elation and gratitude from my son! He came over and hugged and thanked me for taking him riding.

Back home I noticed that parked, the engine will continue to run longer than I think reasonable with the selector in OFF.

1- Is this leaking something that I need to correct or a faculty of an incorrect starting procedure?
2- What’s the best way to clean the fuel residue from the bike?
3- Do I need to look at the selector valve?
 

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1: Where was the leak coming from specifically? The float bowl drains? or the overflow tubes (higher up on the carbs).

2: Probably just have to scrub with soapy water - or spot clean with carb or brake cleaner or you could try this, which is a spot detailer, but I use it on everything and it works well.

Spray Polish.jpg

3: Probably. The bike will run (idle) longer than you would expect with the valve off. But there's a caveat to your fuel valve. The lever you turn could be bad (but it would likely leak out of it before it allowed fuel to flow unstopped into the carbs), OR the vacuum diaphragm could be old and hardened. It takes vacuum from the intake to allow flow to the valve. So in essence, you have 2 means of stopping fuel flow in one device. The diaphragm is replaceable, but a bit costly. Make sure it's bad by taking it apart and seeing if its "petrified".
 

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Discussion Starter #3
It looked like it was dripping from the bottom of the carb where a nipple should be located.

Did you intend to include a link to the spot cleaner?
 
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It looked like it was dripping from the bottom of the carb where a nipple should be located.

Did you intend to include a link to the spot cleaner?
:rotfl: Yup! sure did forget that, but it's there now....just a photo, but I think Amazon sells it great product. I use it on my rims, fairings, everything.


The float bowls have a tapered screw to drain them. Sometimes they have o-rings on them too. Make sure they're not damaged, and make sure the tapered area isn't corroded.
 

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Discussion Starter #5
I could see having one, maybe 2 simultaneous failures, but 4 all at once?!?? I will check with my wife but I think she would have said something if it leaked when she last rode it (scratches head thinking who rode it last).
 
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I could see having one, maybe 2 simultaneous failures, but 4 all at once?!?? I will check with my wife but I think she would have said something if it leaked when she last rode it (scratches head thinking who rode it last).
Maybe they were left open after draining the carbs for the winter? I agree that all 4 leaking is strange, but it happens. Maybe the fuel is leaking from up top somewhere and just noticeable at the float bowl drains :idunno:

I'm sure you'll get to the bottom of it :nerd
 

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Discussion Starter #7
Are you saying they are supposed to be normally closed? We bought the bike this past Autumn. I haven’t turned a wrench or screw on it- not even washed it yet. Only put gas and Stabil in it this far.

After this mystery I plan to install the Battery Pigtail and put a cover on it. It’s probably due for an oil change just in the passage of time.
 
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Are you saying they are supposed to be normally closed? We bought the bike this past Autumn. I haven’t turned a wrench or screw on it- not even washed it yet. Only put gas and Stabil in it this far.

After this mystery I plan to install the Battery Pigtail and put a cover on it. It’s probably due for an oil change just in the passage of time.
Yes, they should all be snugged up nice. :grin
 

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Discussion Starter #9
Perhaps they vibrated loose. I’ll check them this evening. Thank you sir!
 
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Discussion Starter #10
Bike is now in the shop with a 10hr labor estimate (oil change, general maintenance, carburetor cleaning, fork oil change). Wife doesn't ride it and the shop's policy is warranty void if bike isn't ridden 100miles/mo. It will happen again, just little time and interest in riding it- I have put more miles on it than she has and my riding time is spread out over a couple other bikes. I'm selling one to help with that problem.

Should these carbs be drained between sessions when it's not ridden? Can I simply shutoff the petcock and have the fuel ingested through the engine to prevent future issues? What's the easy solution?
 

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Why does it need a carb cleaning? Just from it sitting so long?

Yes, a bit of stabilizer in the tank and run it for a few to get some into the carbs then shut the valve off and let the carbs run out. It won’t get all the gas out, but should get enough out to get a good start up the next time you take it out.

Dealers have become extremely picky these days. 10 hours seems like highway robbery, but in 2002 we had a policy that we didn’t work on anything made prior to 1990. And we charged “actual time”, so if it took the tech 30 hours to clean carbs, fork seals, wheel bearings, tires, brakes and a battery on your 78 GL1100 Goldwing, you just spent 3 times what is was worth BUT, people did it.
 

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Discussion Starter #12
Sounds like you're implying that it's been improperly diagnosed. Reading over the thread may indicate the same. Having some trust in the shop owner's integrity and a bit of my own laziness and being inundated with other things, I'm biased to go with their recommendation.

I do think it interesting that they said the fuel selector needs a rebuild/ replacement on their estimate; I'd agree with that and it lends some credibility.
 

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Looking back at your last post, it’s been 2 years. So if you haven’t put more than 100 miles on it since then a carb clean could be in order if it’s not running well and is still leaking.
 

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Discussion Starter #14
That's the thing: It's runs FANTASTIC, except when cold. After it warms up and gets a few miles, the leak stops too.
 
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Seems typical of an air cooled engine to me, save for the leaks. Hopefully for the price it will be better than new, and not leak....
 
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