Author Topic: Petcock leaking, another don't overlook the easy fix.  (Read 432 times)

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Offline Don R

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Petcock leaking, another don't overlook the easy fix.
« on: April 24, 2024, 03:52:47 PM »
  So I have this cb750K2 with a leaky petcock, I don't ride it much and am trading it to my brother for an engine I don't want, therefore it needs fixed. I rebuilt it recently but bought another kit, obviously made in china. I removed the valve, sanded the tank bottom, cleaned the petcock top, replaced the o ring, put it back in.  Now it has aluminum tank screw to petcock body washers. They leaked through, I greased them and overtightened them with my JIS screwdriver. They finally appear to hold but the sediment bowl still leaked. Several different tries and o rings later, I left it turned off and blew into the gas line. Fuel sprayed sideways out of the sediment bowl. L0L!
 There is a tiny pinhole in the bowl. I swapped it with another one and, it's finally fixed.
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Offline Johnie

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #1 on: April 24, 2024, 04:47:46 PM »
Atta boy Don...don't those issues just drive a guy nuts. Nice job!
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline bryanj

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #2 on: April 24, 2024, 04:52:50 PM »
Those original fiber washers are expensive but do work, i also had hit and miss results with alloy washers, even the ones with rubber inserts known in uk as "Dowty Washers"
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Online CycleRanger

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #3 on: April 24, 2024, 07:34:48 PM »
There is a tiny pinhole in the bowl. I swapped it with another one and, it's finally fixed.

Yep, I have run into that. Pin hole in the sediment bowl from corrosion over time.
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CB750K5        '79 XL250s     CL350K3
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Offline newday777

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #4 on: April 25, 2024, 02:16:59 AM »
There is a tiny pinhole in the bowl. I swapped it with another one and, it's finally fixed.

Yep, I have run into that. Pin hole in the sediment bowl from corrosion over time.
I'll have to put an air air pressure test to the one I cleaned up last year that was very full of powder when I took it off the tank. It cleaned up well in the ultrasonic cleaner amazingly. (I thought I had pictures of it after cleaning but will take new pics and post later)
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 dave500

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #5 on: April 25, 2024, 03:41:08 AM »
i use copper washers,work fine.

Offline newday777

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Re: Petcock leaking, another don't overlook the easy fix.
« Reply #6 on: April 25, 2024, 11:47:03 AM »
There is a tiny pinhole in the bowl. I swapped it with another one and, it's finally fixed.

Yep, I have run into that. Pin hole in the sediment bowl from corrosion over time.
I'll have to put an air air pressure test to the one I cleaned up last year that was very full of powder when I took it off the tank. It cleaned up well in the ultrasonic cleaner amazingly. (I thought I had pictures of it after cleaning but will take new pics and post later)

The ultrasonic cleaning results
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