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Author Topic: Carb issues  (Read 694 times)

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Offline rappz7

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Carb issues
« on: September 18, 2016, 10:21:47 am »
I have a 1979 cb650 and got to the start up phase yesterday after a long build. I used a remote tank and went to start her up when gas started to pour from the carb bleed nipples at the bottom as is the screws were fully open. From the left it was the 1st and 3rd carbs that were leaking I believe. What could be causing this? The engine will run with a couple spurts of starting fluid but quickly dies again after it uses that up. Am I going to have to tear the carbs apart? Such a pain in the ass getting to those carbs, very involved. I was wondering if this is simpler than taking them apart? All advice welcomed and appreciated.
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Offline DaveBarbier

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Re: Carb issues
« Reply #1 on: September 18, 2016, 01:21:13 pm »
The tubes on the bottom of the carb? Those are overflow tubes, not bleed nipples.

Sometimes after the carb bowl is run dry the floats stick in the down position. As fuel is flowing in you can try giving the offending bowls a rap with a screw driver handle. That can unstick the floats.

It's also possible that the float needles have grit on them preventing them from sealing. Obviously a very clean tank is needed to prevent crap fro clogging up the carbs.

The engine dying is another issue that could easily be carb related but also might be ignition related. If I were you I'd remove the carbs and remove all jets and IMS and such and thoroughly clean the carbs.
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Offline rappz7

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Re: Carb issues
« Reply #2 on: September 18, 2016, 03:53:05 pm »
Thanks for the info DaveBarbier I gave one of the carbs or good wrap and it seemed to stop leaking not as lucky for the other one though. If i cant get em to stop leaking ill take em off and clean them
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Offline flybox1

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Re: Carb issues
« Reply #3 on: September 18, 2016, 06:05:32 pm »
all the carb cleaning in the world wont help if you have debris and a i#$%*ty in-tank fuel filter.
debris will cause float valves to hang up and not shut off your fuel.
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Offline rappz7

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Re: Carb issues
« Reply #4 on: September 22, 2016, 03:01:25 pm »
Quote from: flybox1 on September 18, 2016, 06:05:32 pm
all the carb cleaning in the world wont help if you have debris and a i#$%*ty in-tank fuel filter.
debris will cause float valves to hang up and not shut off your fuel.

Thanks for the input. Im going to remove that in take filter and replace it with a nice in line one when the tank goes back on. For now im using a remote tank as I try and work out the many issues Ive ran into since first start up.
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