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Author Topic: CB350f petcock problem?  (Read 2626 times)

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Offline Johnny5

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CB350f petcock problem?
« on: May 21, 2017, 05:40:10 PM »
Hello all,

So I installed new OEM orings on my petcock and no matter what, the petcock leaks from the upper body of the petcock where it meets the bottom of the gas tank. So I took off the petcock again to inspect what's going on. Upon a closer look, I found the middle of the petcock where the oring sits looks distorted.

Posting these pics to see if this is normal or not. Looks like the cause of my leak.


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1971 CB350
1973 CB350F
2006 Harley Springer Classic

Offline Johnny5

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Re: CB350f petcock problem?
« Reply #1 on: May 21, 2017, 09:37:28 PM »
I'm going to replace this part. After seeing other pics, it just doesn't look right.

Can I use a cb550 or cb750 petcock instead? I can hook up a 2 into 1 splitter for the fuel line.
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1971 CB350
1973 CB350F
2006 Harley Springer Classic

Offline Johnny5

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Re: CB350f petcock problem?
« Reply #2 on: May 26, 2017, 05:14:41 AM »
Since I couldn't find a replacement 350F petcock and the rebuild kit wasn't working, I bought a 750 to see if I can get it to work.

Good news, no leaks. My 350f petcock is trashed.

Bad news, the brass tubes with fuel lines connected collide with the carbs. So I need to block off one of the outlet tubes and install a 90 degree elbow in the other. Another thought was to block off both outlet tubes and drill and tap an outlet tube where the red arrow is pointing. Don't know if that will ruin the petcock though.

And I don't know where to find brass tubing.

Any thoughts?

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www.kerosenecycles.com
1971 CB350
1973 CB350F
2006 Harley Springer Classic

Offline madmtnmotors

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Re: CB350f petcock problem?
« Reply #3 on: May 26, 2017, 07:10:45 AM »
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TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline Corey_lax

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Re: CB350f petcock problem?
« Reply #4 on: May 26, 2017, 07:42:06 AM »
@Johnny5, would you be willing to sell your old broken petcock valve? The thumbturn portion of mine is broken. I'd rather not swap it out to the "two outlet" model.
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Offline Johnny5

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Re: CB350f petcock problem?
« Reply #5 on: May 26, 2017, 08:33:02 AM »
Possibly. The lower parts are fully rebuilt and functional. Pm me.
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1971 CB350
1973 CB350F
2006 Harley Springer Classic

Offline Johnny5

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Re: CB350f petcock problem?
« Reply #6 on: May 26, 2017, 12:48:51 PM »
Yeah, I did find that one but they are out of stock. Was hoping to get my bike on the road this weekend too.

Quote from: madmtnmotors on May 26, 2017, 07:10:45 AM
This one looks like it has shorter outlet connection tubes:

http://4into1.com/reproduction-fuel-valve-petcock-16950-300-020-honda-cb350f-cb500k-cb550k-cb750k/
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www.kerosenecycles.com
1971 CB350
1973 CB350F
2006 Harley Springer Classic

Offline madmtnmotors

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  • Really Old Timer ...
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  • Sunny Central Florida
Re: CB350f petcock problem?
« Reply #7 on: May 26, 2017, 02:06:22 PM »
Quote from: Johnny5 on May 26, 2017, 12:48:51 PM


Quote from: madmtnmotors on May 26, 2017, 07:10:45 AM
This one looks like it has shorter outlet connection tubes:

http://4into1.com/reproduction-fuel-valve-petcock-16950-300-020-honda-cb350f-cb500k-cb550k-cb750k/

Yeah, I did find that one but they are out of stock. Was hoping to get my bike on the road this weekend too.


Duh-oh! I failed to read the entire description...  :-[
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TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline Johnny5

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    • CB350F build thread
Re: CB350f petcock problem?
« Reply #8 on: May 26, 2017, 10:29:04 PM »
Doing a test on the original petcock. I lightly coated the boring with some Threebond and 8 hours later not a single drop has leaked. Maybe it was salvageable. If it gets me by long enough to source another one, I'll be happy. Really want to get it out on the road tomorrow.

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www.kerosenecycles.com
1971 CB350
1973 CB350F
2006 Harley Springer Classic
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