Author Topic: Keihin 29mm CR special carburetors….  (Read 1533 times)

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Offline jorgholio

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Keihin 29mm CR special carburetors….
« on: September 12, 2021, 08:06:27 AM »
I have a  71 cb 750 K1 and I’m looking to install these new carbs.
Has anyone installed these carbs before? And if so, where or how to you install the two fuel lines coming of my fuel petcock?
I see a 90 degree spigot on #1 carb, there another straight between 1&2, one between 2&3 and another between 3&4
If anyone has installed these before your input would greatly appreciated.
Regards

Offline per

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Re: Keihin 29mm CR special carburetors….
« Reply #1 on: September 12, 2021, 08:21:53 AM »
Hi
When I replaced the carbs on my 1975 cb 500 I had the same issue. I solved it by simply make a new spigot with with a 6 mm tube poking out at 90 degress to taka an additional fuel line. I made it out of brass and just soldered with soft radio solder.
Works perfectly.
Per
"Of course they are faster than me. They are young, fit and fearless, I am old, fat and scared!"

Offline newday777

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Re: Keihin 29mm CR special carburetors….
« Reply #2 on: September 14, 2021, 03:30:44 AM »
I have a  71 cb 750 K1 and I’m looking to install these new carbs.
Has anyone installed these carbs before? And if so, where or how to you install the two fuel lines coming of my fuel petcock?
I see a 90 degree spigot on #1 carb, there another straight between 1&2, one between 2&3 and another between 3&4
If anyone has installed these before your input would greatly appreciated.
Regards
No instructions came with the CRs? Are the new or used?
So there are 3 spigots on these carbs according to your description?
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A

Offline richmagee7

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Re: Keihin 29mm CR special carburetors….
« Reply #3 on: September 14, 2021, 03:51:19 PM »
I recently installed CR26 carbs on my CB500.  Two lines coming from petcock.  I ran one line to the tee between 1 and 2, and the other line to the tee between 3 and 4, then capped the tee between 2 and 3.  I forget what I read the 90 degree spigot is, but it is not for fuel.  Air intake for choke possibly.

Offline MRieck

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Re: Keihin 29mm CR special carburetors….
« Reply #4 on: September 15, 2021, 03:00:12 AM »
I recently installed CR26 carbs on my CB500.  Two lines coming from petcock.  I ran one line to the tee between 1 and 2, and the other line to the tee between 3 and 4, then capped the tee between 2 and 3.  I forget what I read the 90 degree spigot is, but it is not for fuel.  Air intake for choke possibly.
That's how you do it. Those 90 degree spigots are for the fuel enrichment system (choke). I highly recommend running lines about 1.5 feet long on them to prevent crud from getting in there. Crud will prevent the valve from fully sealing and cause all sorts of fueling problems that will have you pulling your hair out.
Owner of the "Million Dollar CB"