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Latest post Fri, May 18 2018 3:04 PM by FX. 19 replies.
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  • Wed, May 16 2018 2:52 PM

    • FX
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    Steve, help

    This 883 butterfly carb is driving me nuts. I must have rebuilt a dozen of these over the years. I can't make this thing stop leaking out the overflow. The needle is new, seat is clean. I did a make-shift pressure, and leak-down test on the bench, all is well. I've tried the float level at various hights, no luck. I put it back on the bike, and it leaks out the overflow when it's on the side stand, straight up it's okay. The float itself does not seem too heavy, like watter (gas) logged. I really don't want to take the float hight down too low. Was there anything chronic with these old carbs that I should look for? Any tricks that you know of?

    FX

    Don't force it, get a bigger hammer.

  • Wed, May 16 2018 3:15 PM In reply to

    Re: Steve, help

     if the needle and seat are good, it just about has to be the float. worn mount tabs, gas logged [too heavy] or just worn out. i looked around for a float, could not find a part number. oem number is 27887-78. something else i noticed while i was looking around, there is a seat cutting tool for that carb, to correct any deformation of the seat. v twin number is 16-0095, we don't carry it here. is it possible that although the seat looks clean, it is deformed?

     

  • Wed, May 16 2018 3:31 PM In reply to

    • FX
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    Re: Steve, help

    No Steve, the needle and seat hold air, so there wouldn't be a problem with the seat. I have felt heavy floats before, and this one doesn't seem logged, but I could be wrong. If it is, it's not much, and I should be able to adjust the hight accordingly. I'll see if my local dealer can get that number, but I don't think that's what it is. I actually had the leak stopped on the side stand, but when I jiggled the bike, it leaked. I took the carb back off again (for the 5th time) and lowered the level just a little, it was worse when I put it back on the bike...It almost seems like the float is sticking, but I can't find any evidence of that...

    FX

    Don't force it, get a bigger hammer.

  • Wed, May 16 2018 3:43 PM In reply to

    Re: Steve, help

     i'm wondering if the float tabs are worn, allowing the float to move back and forth when you jiggled the bike,  and that's moving  the needle enough to make it leak?

     

  • Wed, May 16 2018 4:05 PM In reply to

    • FX
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    Re: Steve, help

    I don't think so Steve, I was just out there checking that vary thing. I found a new float. My local Harley dealer has a contact that buys up obsolete parts (NOS). He can have it here in a few days. It's only a 15 dollar gamble, but I don't think that's what it is. I'm trying to give you all the clues I can. Let me know if you come up with any more ideas.

     

    FX

    Don't force it, get a bigger hammer.

  • Wed, May 16 2018 4:05 PM In reply to

    Re: Steve, help

     i plugged that oem into a local dealers website, came back not available. try Bill's custom cycle in pennsylvania, he spent decades buying up obsolete parts from dealers, he has pole buildings full . i have found all kinds of wierd and obsolete parts there. he has a nice museum too

     

  • Wed, May 16 2018 4:12 PM In reply to

    • FX
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    Re: Steve, help

    Steve, see above...

     

    FX

    Don't force it, get a bigger hammer.

  • Wed, May 16 2018 4:42 PM In reply to

    Re: Steve, help

     been a busy day, i'm heading home shortly. i'll stew on it over a cold beverage at the magic picnic table in my back yard and check in with you in the morning.

     

  • Wed, May 16 2018 6:05 PM In reply to

    • Ironhead
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    Re: Steve, help

    To make sure the seat isn't deformed, could you take some valve lapping compound and use the old needle to lap the seat?

    The first tool out of the box should be the "book"  Geeked

  • Thu, May 17 2018 6:09 AM In reply to

    • FX
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    Re: Steve, help

    I had actually thought of that Keith, but the needle/seat hold air pressure and vacuum. This is how I always check them, it has never failed me. The key here is that it doesn't leak when the bike is straight up, only on the side stand. I have tried various float hights...I don't think there's a crack in the housing cause the gas leaks out the overflow, not the body...I know, I know, only me...

    An indication that the needle/seat is good is that with a full tank of gas, and some pressure behind it. and the bike straight up, it doesn't leak.

    The bike needs a lot of other work too, but I am fixated on this damn leak enigma. I refuse to give up, and throw a new carb on it, the engine runs real good with this one. This would be a good test for my carb rebuild class 101. But I don't as of yet have the answer...

    FX

    Don't force it, get a bigger hammer.

  • Thu, May 17 2018 6:47 AM In reply to

    Re: Steve, help

    good morning. process of elimination. if needle, seat and float are good, then bowl should not over flow. if it is, then fuel has to be entering the bowl from somewhere. if i remember correctly, the fuel inlet is above, in the body. so, where, between the inlet and the bowl, could fuel be entering?  i assume the bowl gasket is good, have you taken a good look at the body?

     

  • Thu, May 17 2018 8:44 AM In reply to

    • FX
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    Re: Steve, help

     Good morning Steve. Yes, good look at the body with magnifying glass, and yes, the inlet is above the bowl, but it's only leaking out the overflow on the side stand. Good point, looking outside the box, and eliminating the needle/seat. All new gaskets, no leaks there. With full tank of gas,  the bike straight up on the jack, and the float level on specs, I left the fuel valve on over night, no leak until I put it down on side stand. I lowered the float a little more, and still leaked on the side stand. I don't want to lower the level too much, and not leave enough gas in the bowl to run properly...

    Like I said, I found a NOS float for it that can be order in. My nephew wants to see if they have a NOS carb for it. I'm really stuborn when it comes to things like throwing parts at something I can't fix. I'm a better mechanic than that. Plus this thing's got me po'd...

    FX

    Don't force it, get a bigger hammer.

  • Thu, May 17 2018 8:58 AM In reply to

    Re: Steve, help

    yep, been there done that one. another thought, if i remember correctly, isn't the over flow tube pressed into the bottom of the fuel bowl? what if it was loose, and when the bike leaned over, the tube moved, allowing fuel from the bowl to go directly from bottom of bowl to overflow?

     

  • Thu, May 17 2018 9:00 AM In reply to

    Re: Steve, help

    i have to go run some errands, i'll check back in later

     

  • Thu, May 17 2018 9:09 AM In reply to

    • FX
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    Re: Steve, help

    Yes, pressed in, and tight. The overflow tube exit is actually higher than the float chamber top, and way higher than the fuel level at specs... But with your scenario the fuel level in the bowl would still have to be way too high...

    I'm gonna go get lunch now, I'll check back later...

    FX

    Don't force it, get a bigger hammer.

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