Author Topic: 1973 Honda CB350F prtcock rebuild  (Read 1756 times)

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Offline zcb350fb

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1973 Honda CB350F prtcock rebuild
« on: February 02, 2018, 06:43:09 PM »
My Percocet had a slow leak out of the gas outflow tube when left in the off position. I purchased a rebuild kit from 4into1. They give you all the parts you need and then others you don’t depending on what model you have. I took my pet coco apart and cleaned it. I replaced the parts with the new ones in the same order the old parts were. I found a decent diagram of how the petcock goes together on google. This is the diagram I found and followed. The petcock still has the leak after the rebuild. Could I have missed something? Does anyone have detailed steps/pictures/tricks on how to rebuild this properly? For example the brass screen has two nubs sticking out on one side of it. What are these for and do the set towards the tank or towards the ground? Next does the o-ring sit under the screen and then do you screw the bowl in or do you wrap the o-ring around the bowl and then screw the bowl in? Can you over tighten the bowl? Any help would be greatly appreciated.

Rebuild kit I bought http://4into1.com/petcock-rebuild-kit-honda-cb160-72-77-350f-500k-550k-750k/

Diagram I found and used for reference http://images.cmsnl.com/img/partslists/fuel-tank-cock-cb350f-four-general-export_bigma000079f11_07ef.gif
1973 cb350f

Offline zcb350fb

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #1 on: February 02, 2018, 07:02:23 PM »
So basically after rebuilding the petcock, the same leak out of the exterior gas outflow tube is still there. I’d just like to know if I’ve rebuilt it wrong, is there anything else I could do instead to fix it or is it time for a new petcock. Thanks!
1973 cb350f

Offline whizzer

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #2 on: February 02, 2018, 07:15:58 PM »
When I rebuilt mine, it leaked until cleaned it better.  Don't know about screen but recall the large o-ring set inside under screen and top of bowl had to be very clean and smooth to seal well. No need to over tighten, it has to be removed on occasion to remove sediment.  One trick I read was to put thin film of grease on back of on/off plate to ease the action. This helps.  Once set, no leaks for years.
« Last Edit: February 02, 2018, 07:19:40 PM by whizzer »
72 cb350f
66 cb77 sold
72 Suzuki gt750 given away
59 Vespa given away
06 Whizzer sold

Offline Remcod

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #3 on: February 03, 2018, 05:21:31 AM »
What about the o-rings from the 2 screws that fastens the body? Usually not in a repair kit and a source of leakage. Changed those?

Offline zcb350fb

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #4 on: February 03, 2018, 06:30:10 AM »
They did give me two new washers for the two screws in the rebuild kit. The original washers look to be a orange/pink rubber that look to still be in good shape so I didn’t replace them. The new washers are silver metal. Probably crush washers.
After the rebuild the petcock is still leaking slowly out of the exterior gas outflow tube. Would leaks from the screw washers find their way out of that tube?
1973 cb350f

Offline Remcod

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #5 on: February 03, 2018, 06:47:08 AM »
They would and the silver metal washers are much better, I would replace them

Offline zcb350fb

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Re: 1973 Honda CB350F prtcock rebuild
« Reply #6 on: February 03, 2018, 06:52:33 AM »
Awesome
Thank you for the advice guys!
1973 cb350f