Vintage and Classic Hondas

Mysterious "t-piece" between carbs on '81 CB750K...

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Feb 12, 2012; 6:49pm

Re: Mysterious "t-piece" between carbs on '81 CB750K...

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K. Crisman

May 08, 2012; 6:39pm

Re: Mysterious "t-piece" between carbs on '81 CB750K...

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In reply to this post by Ray

I have an 81 CB750C that the fuel diaphragm (vacuum actuated petcock) leaks out the top bad... can the part be bypassed and just rely on turning the manual petcock to "off"?

LukeM

May 08, 2012; 8:32pm

Re: Mysterious "t-piece" between carbs on '81 CB750K...

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In a word, yes. You will need to use the petcock all the time. Just unplug the hose going from the petcock to the fuel vacuum valve, and put it where the output of the fuel vacuum valve goes to. Should be pretty easy to find and to bypass.

I had one on my CB750L, and the only time it was a problem was if the carb bowls were dry. It would take quite a bit of cranking to get enough vacuum pulses to the valve to allow gas to get to the carbs. If I were riding it regularly, there was plenty of gas in the carbs, and starting was less of an issue.

Luke M

Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.

cdaiscool

May 09, 2012; 1:58am

Re: Mysterious "t-piece" between carbs on '81 CB750K...

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Also make sure to block off the vacuum nipple coming off the 2nd carb. I'm doing this to my carbs as well.

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