Leaking 1939 Left Hand Gas Tank Valve

[Bill D.]

I have a 1939 Knucklehead and the left hand gas valve has leaked since I obtained the bike (about 1 year). The valve has a brass body and steel tapered plug which I believe to be a 3601-36. I am not sure if it is stock or aftermarket as I am not a knucklehead person. I lapped the plug to the body with 320 grit clover compound cut with light oil to thin it out (which was the finest grit I had), followed by AutoSol and then Brasso. When I examine both the body and the plug under a magnifier - both finishes look good but it still weeps at the front of the valve (the larger diameter). Does anyone have any ideas or methods for this type of issue.
You can respond to the forum or email to dok@valornet.com
Thanks in advance for any help.

[Chris Haynes]

Your problem is a common one. Some folks do some machine work and install "O" rings. I can't recommend anybody who does it though.

[Bill D.]

Thanks Chris - I am not surprised at your comment. Any debris would score the brass for sure. I am thinking about building a tephlon insert. I went online and it appears that the small vessel marine industry used similar valves but they also used an oring seal. I appreciate your response thanks.

[Eric MATHIEU]

I lapped mine with valve lapping compound and oil and then I pulled the spring to make it longer/stronger and now no more leaks.
Eric

[Bill D.]

Eric, what grade lapping compound did you use? Thanks I appreciate the insight. I am waiting on 1200 grit compound. When I lapped with the 600 grit I still had very minor seepage.

[Bill D.]

I made mistake on the grit I used it was 320 grit.