Can I put a shutoff valve on the overflow tube? - Honda Rebel Forum
 
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post #1 of 10 Old 05-10-2020, 09:22 AM Thread Starter
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Can I put a shutoff valve on the overflow tube?

My mother's rebel 250 regularly leaks after rides, even though she had a shop completely redo the carb after an improper winter storage. We brought it back the first time it leaked and they said they couldn't find anything wrong, and it doesn't always leak. I assume it's a stuck float valve. It leaks a bit even when I turn off the petcock, if that changes things.

If I add a small shutoff valve to the end of that fuel line, we can stop it from leaking in the garage but still empty to carb for storage. Am I missing some basic reason that's a bad idea? Some necessary purpose to letting it overflow out of the bike?
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post #2 of 10 Old 05-10-2020, 10:37 PM
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Welcome to the forum. Is your mother's Rebel a California model? Can you post a pic of exactly where it is leaking? If it is the carb overflow tube, I would not put a shutoff valve there. This wouldn't fix why it's leaking and could allow fuel to reach the crankcase, wash the oil off the rings, dilute the oil, and overfill the crankcase. Try tapping on the carb bowl with a screwdriver handle. That will sometimes unstick a hung up float valve. The petcock may or may not be bad. On the next ride, have your mother turn the petcock to off about a 1/4 mile before reaching her destination. This will use up most of the fuel that's already in the bowl. If gas still drips out of the overflow tube, the petcock is leaking, and I suggest replacing it. A Rube Goldberg alternative would be to install a shutoff valve on the fuel line from the tank.

It's possible that the shop didn't replace the float valve or the new one isn't sealing as it should. I suspect they charged quite a bit to rebuild the carb, and they should stand behind their work.

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post #3 of 10 Old 05-11-2020, 10:27 PM Thread Starter
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Thanks. Part of the problem was the petcock was letting a trickle of gas through even in the off position. I've just ordered a new one to fix that problem. The carb float pnly sticks sometimes (although when it does the screwdriver trick doesn't work), so when we brought it back to the shop it didn't leak and they couldn't find a problem. Maybe I'll bring it back again.
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post #4 of 10 Old 05-12-2020, 12:21 AM Thread Starter
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I did some more research, and I might have used the wrong term. The leak is coming from the tube that you can use to drain the carb. I thought that was also called the overflow, but I read that's actually a different tube? So if the leak isn't actually from the overflow, would it still be caused by a stuck float, or is it the carb drain valve leaking somehow?

Either way I'm replacing the petcock, because the leak should have emptied out the carb then stopped.
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post #5 of 10 Old 05-12-2020, 12:47 AM
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Here's a pic of the carb hoses. The carb overflow and drain tubes are connected by a Y fitting.

https://jayshah.smugmug.com/Odds-and...9P/i-2KML4wC/A

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post #6 of 10 Old 05-12-2020, 12:48 AM
 
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The tube at the bottom of the float bowl is the float fowl drain when the drain screw is loosened. The drain screw may be in poor shape, shut off the fuel and get the drain screw out for examination.

Also inside the float bowl is a vertical tube that leads to the same drain hose, this vertical tube only let's so much fuel into the float bowl before it begins to act as an overflow drain. This vertical tube can sometimes crack and leak. You'd need to remove the float bowl to inspect for cracks.

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post #7 of 10 Old 05-19-2020, 11:30 AM Thread Starter
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Thank you. The screw looks fine, so it's probably the carb float. I'll get it checked out at some point, but with a working petcock that shouldn't matter too much.

About the petcock, the one I ordered has a shirter intake tube and a white filter that fits over it, but the petcock fits into place fine. I assume this just means I'll have less reserve?
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post #8 of 10 Old 05-19-2020, 01:22 PM
 
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Yes, shorter tube = less reserve, and more miles before reserve.

This petcock filter may catch more fine particulates that could be fouling your float needle causing these conditions in the first place.

Another thing that can cause this is a hole in your float, if there's a hole the float can fill up with gas and sink.

Testing carb floats consists of removing them, holding them underwater looking for bubbles to rise as you turn the submerged float this way and that, then after a minute you let it float free, if its waterlogged and sinks = bad.

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post #9 of 10 Old 05-19-2020, 06:06 PM
 
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You may need to replace the float, or just the float needle. I'd order the carb kit from Jack's (rebelcatalog.com) and change things out if you have it out and are getting it cleaned and such anyway.

Do you have a fuel filter in the line between petcock and carb?

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post #10 of 10 Old 05-22-2020, 03:12 PM Thread Starter
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I didn't have an inline filter before but I just added one when I did the petcock.
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