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xr650r overflowing

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I can't figure out what the problem is. I've had this carb apart at least 6 times in 6 weeks. the damm thing keeps pissing fuel out the overflow. i checked the floats they are okay. checked the overflow its sealing up. i can hear the floats moving after the carb is assembled. it will stop for a little while, then do it again. could this be the accelerator pump?

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stock, and i know its GOTTA be the floats, but i checked the seal with the bowl off, and it doesnt leak, floats move freely, i dont see holes in them, and nothing leaks out of the float. im stumped

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while off bike and bowl off have you checked with fluid this way? maybe just time to order new piece for it, seal may look ok but not be

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If the float is adjusted right, there may be some crud in the valve. I use a paper towel and clean the tip of the needle valve. Then twist up a paper towel and use it to clean the seat of any crud that might be there. Don't go overboard on cleaning though. If you use something metal be very careful not to scratch anything.

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I have the exact same problem! :) Been battling my @ss off. Running 172 main, 68s, 3rd clip. Few drops (2-3) of petrol drips from the overflow while kicking the bike over. Since I have uncorked the bike I have had endless problems starting it.

Checked valves, crud in the carb, kinked hoses, spark etc etc.

Am I correct in saying that the float should be level with the gasket/bowl surface and just touch the float valve tip, the distance is 18mm?

Well, ordered the Clymer manual with the hope that it has one hell of a troubleshooting flow chart to solve this problem.

Unless some of the experienced and respected guys over here can assist.

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Apologies for asking the obvious here, which part(s) on the diagram would that be. Newbie on this.

CarbExpl.jpg

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Your float might be sinking. Take the float off and set it in the float bowl with gas and simply see if it floats. I have seen this a few times over the years.

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Needle and seat needs replacing on both bikes.

It's been my experience over the years at a good cleaning will usually fix it. I'm not talking just squirting with carb cleaner. If that doesn't fix it or if the tip of the float valve is obviously screwed up, then replace them.

It can be done without even removing the carb from the bike.

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Apologies for asking the obvious here, which part(s) on the diagram would that be. Newbie on this.

CarbExpl.jpg

It would be the item labeled float valve which is attached to the float itself. If the float valve is not properly seated when the bowl is full of fuel, it will continue to let fuel in, thus, fuel will continue to spill out the vent. Make sure the float valve and its seat are clean and properly attached. If so, float may be saturated and "sinking" which would also let unwanted fuel into the bowl and again, out the vent. I'm guessing you have something going on with the float valve.

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i checked it with the carb off i raised the floats (to close the valve) and dumped water into the carb inlet (from petcock) no leaks. release the floats and the water comes running out. I'm gonna take it off again and see if there is debris i didn't see the first 6 times. i thought maybe the floats are cracked and sinking as well, but i dont see any cracks, and they are not filled up with gas.

thanks for your input, the problem seems obvious, but everything seems to be functioning like it should...

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i checked it with the carb off i raised the floats (to close the valve) and dumped water into the carb inlet (from petcock) no leaks. release the floats and the water comes running out. I'm gonna take it off again and see if there is debris i didn't see the first 6 times. i thought maybe the floats are cracked and sinking as well, but i dont see any cracks, and they are not filled up with gas.

thanks for your input, the problem seems obvious, but everything seems to be functioning like it should...

It should take very light pressure on the float to make the float valve seat correctly. If you have to put more than light pressure on the float to close the valve, then you might consider changing the valve and seat. That is, if your float level is set correctly and everything is clean.

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You ran water through your carb!!!

Try hooking up the carb with a new needle and seat take off the float bowl and trying it with PETROL.

Had the float been sinking you would of seen it weighed too much and was full of fuel.

Other than this have a nice day.

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test the float, with the bike on a stand. get a clear line put it on the drain on the bottom of the bowl. then run it up the side of the carb with the open side pointing up and higher than the carb. see how high the gas go's up in the clean fuel line. if it flow out the top its the float valve. my 0.02

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You ran water through your carb!!!

Try hooking up the carb with a new needle and seat take off the float bowl and trying it with PETROL.

Had the float been sinking you would of seen it weighed too much and was full of fuel.

Other than this have a nice day.

yeah, its not a big deal it goes right from the inlet through the valve. it cleans right out with brake cleaner, and is better then letting gasoline right out the bottom onto the floor (since bowl is off)

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The float is solid. You won't see a crack it will just be saturated.But then again this is more common on like a car carb,say a GM qudra jet.

like a few have said,sounds like the needle and seat.

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test the float, with the bike on a stand. get a clear line put it on the drain on the bottom of the bowl. then run it up the side of the carb with the open side pointing up and higher than the carb (edit & open the bowl drain). see how high the gas go's up in the clean fuel line. if it flow out the top its the float valve. my 0.02

+1 simple, easy and damn near foolproof :banghead: it will show the actual level or if there is a leak. :)

i've read where BWB and other have adjusted their level slightly below the factory level spec for occasional pizz'n...

...but if ur is doing it constantly it's most likely a float, needle & seat issue.

...there is one other possibility, ur bowl drain might not be sealing.

:banghead:

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test the float, with the bike on a stand. get a clear line put it on the drain on the bottom of the bowl. then run it up the side of the carb with the open side pointing up and higher than the carb. see how high the gas go's up in the clean fuel line. if it flow out the top its the float valve. my 0.02

I'd never heard of that. Helluva cool idea! :) Deserving of a little extra fuel I'd say.

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