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Old 08-16-2008, 12:18 PM   #1
Shinglejohn
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Default CM400 carbs leaking from overflow

I keep having theis problem with the bike leaking from the overflow hose on the carb while it is at idle. it doesnt leak while riding.

when it happens i take the carbs out and clean the float needle seat and it works for a while but it always comes back. im pretty sick of tearing the carbs out. any ideas?
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Old 08-16-2008, 12:55 PM   #2
sarnali2
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your floats may be set too high, try setting them a little lower or the needle or seat may be worn to the point where they don't seal completely. Try setting the floats a little lower first, if that doesn't work I'd try new needles.
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Old 08-16-2008, 10:27 PM   #3
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Originally Posted by sarnali2 View Post
your floats may be set too high, try setting them a little lower or the needle or seat may be worn to the point where they don't seal completely. Try setting the floats a little lower first, if that doesn't work I'd try new needles.
That, or clean the tank and fuel-lines ahead of the carbs of any/all crap that's coming down the line and jamming the needles open.
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Old 08-17-2008, 01:10 PM   #4
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how should i go about cleaning out the tank?
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Old 08-17-2008, 02:07 PM   #5
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Take the tank off the bike. Remove the petc0ck and everything else bolted to the tank, and plug all the holes. Get a large handful of small bolts. Put 'em in the tank, and then shake that tank for an hour or so. (Seriously.) Then flush out the crap you knocked off, and do it again.
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Old 08-17-2008, 02:36 PM   #6
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Take the tank off the bike. Remove the petc0ck and everything else bolted to the tank, and plug all the holes. Get a large handful of small bolts. Put 'em in the tank, and then shake that tank for an hour or so. (Seriously.) Then flush out the crap you knocked off, and do it again.
That goes to say, you should first drain the gasoline from the tank, and perhaps give it a thorough rinse.

Rustworms will return once the interior finish has been compromised. Consider one of those treatment kits such as Kreem or coating with POR-15.

Some dislike the Kreem, and have had bad luck. I have had excellent results, the kit did exactly what Kreem said it would, and I currently have one bike with it that I coated nearly 10 years-ago: only thing that's "gone wrong" with it since has been a slight discolouration of the coating due to fuel-additives.

But then, I follow the directions with the kit TO THE LETTER. Perhaps those that detest the kits and have had bad luck with them did not.
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Old 08-17-2008, 02:50 PM   #7
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Quote:
Originally Posted by sachiwilson View Post
Take the tank off the bike. Remove the petc0ck and everything else bolted to the tank, and plug all the holes. Get a large handful of small bolts. Put 'em in the tank, and then shake that tank for an hour or so. (Seriously.) Then flush out the crap you knocked off, and do it again.
Here's a tip I picked up working on the old 77 FXS: Use Sachi's method, but instead of shaking the tank by hand, wrap it in bubblewrap, towels, whatever. Then slide the tank (or tanks, in my case) into a 5 gallon paint bucket. Take the bucket to your neighborhood Home Despot or what have you, and ask them to put the bucket on the paint shaker. 5 minutes of that and there was nothing but bare metal inside.

Hit the store on a weeknight after 8 when the managers are gone. I gave the guy a five-spot for the help.
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Old 08-17-2008, 02:57 PM   #8
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Here's a tip I picked up working on the old 77 FXS: Use Sachi's method, but instead of shaking the tank by hand, wrap it in bubblewrap, towels, whatever. Then slide the tank (or tanks, in my case) into a 5 gallon paint bucket. Take the bucket to your neighborhood Home Despot or what have you, and ask them to put the bucket on the paint shaker. 5 minutes of that and there was nothing but bare metal inside.

Hit the store on a weeknight after 8 when the managers are gone. I gave the guy a five-spot for the help.
Hey! That's an excellent idea! WTF didn't I think O' that?
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Old 08-17-2008, 06:55 PM   #9
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You floats might have a pinhole leak somewhere and are filling with fuel. Take them out and shake them an see if there is any fuel within a float. If so replace the float. If you can't replace the float it's possible to resolder them but it should be done by someone with experience.
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