« previous next »
Pages: [1]   Go Down

Author Topic: Gas leak question  (Read 1546 times)

0 Members and 1 Guest are viewing this topic.

Offline Johnie

  • Really Old Timer ...
  • *******
  • Posts: 8,631
Gas leak question
« on: September 30, 2007, 05:59:25 PM »
1970 CB750KO - going to have the OEM tank repainted and trying to cure a leaking gas cap first.  This is the OEM gas cap on here and I have installed a new gasket under the lid and it still leaks.  I do not fill the tank up to the top, but sloshing gas still comes out after a fill until I run it down a little.  How far does the single phillips head screw under the cap have to go in?  Thanks and I appreciate your ideas on how to cure this.
Logged
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 Bob Wessner

  • "Carbs Suck!"
  • Really Old Timer ...
  • *******
  • Posts: 10,079
Re: Gas leak question
« Reply #1 on: September 30, 2007, 07:33:17 PM »
There are quite a few parts comprising the fuel cap assembly. Are you sure you are not missing any? Do you have access to a parts diagram?
Logged
We'll all be someone else's PO some day.

Offline Johnie

  • Really Old Timer ...
  • *******
  • Posts: 8,631
Re: Gas leak question
« Reply #2 on: October 02, 2007, 04:49:52 PM »
I do have access to the parts diagram.  I will look it over.  Appears all are there.  The guy doing the tank painting said to put a small bead of silicone on the lip of the tank and that should seal it up.
Logged
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 Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: Gas leak question
« Reply #3 on: October 02, 2007, 06:46:36 PM »
Quote from: Johnie on October 02, 2007, 04:49:52 PM
The guy doing the tank painting said to put a small bead of silicone on the lip of the tank and that should seal it up.

Be careful who you take advice from.  Silicone will swell and break down when it comes in contact with gas, which will then get caught in and clog up your petcock filter, or your in-line filter, or if you don't have either, it will clog up your idle jets and circuits causing you to have to pull and clean out the carbs. 
Logged

Offline Bob Wessner

  • "Carbs Suck!"
  • Really Old Timer ...
  • *******
  • Posts: 10,079
Re: Gas leak question
« Reply #4 on: October 03, 2007, 03:04:27 AM »
John,

When you do fill-up, does it take a fair amount of effort to press the cap down to secure the latch? It should.
Logged
We'll all be someone else's PO some day.

Offline Johnie

  • Really Old Timer ...
  • *******
  • Posts: 8,631
Re: Gas leak question
« Reply #5 on: October 03, 2007, 04:34:33 PM »
It takes a little pressure to close it.  I was not sure how far to screw that center phillips screw in under the lid.  I was afraid if I went not far enough the screw would fall out and into my tank.  I see that screw will have an effect on how close that seal is before it contacts the top of the tank.
Logged
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 BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,365
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Gas leak question
« Reply #6 on: October 03, 2007, 05:23:55 PM »
Another reason I am happy I own a K8.  ::)
Logged
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline Johnie

  • Really Old Timer ...
  • *******
  • Posts: 8,631
Re: Gas leak question
« Reply #7 on: October 03, 2007, 06:03:57 PM »
We are all happy for you Bobby... ;D :) ;)
Logged
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 Bob Wessner

  • "Carbs Suck!"
  • Really Old Timer ...
  • *******
  • Posts: 10,079
Re: Gas leak question
« Reply #8 on: October 03, 2007, 06:59:58 PM »
Quote from: Johnie on October 03, 2007, 04:34:33 PM
It takes a little pressure to close it.  I was not sure how far to screw that center phillips screw in under the lid.  I was afraid if I went not far enough the screw would fall out and into my tank.  I see that screw will have an effect on how close that seal is before it contacts the top of the tank.

Are you in a position to take a post a pic of the underside of the lid? Open of course.  ;)
Logged
We'll all be someone else's PO some day.

Offline Johnie

  • Really Old Timer ...
  • *******
  • Posts: 8,631
Re: Gas leak question
« Reply #9 on: October 08, 2007, 04:28:01 AM »
Bob...I could send a picture of the underside lid to your email.  I will do that today.  I mentioned I already installed the new large seal.  Now I ordered a new spring and rubber inner seal.  I really want to keep this vintage cap.
John
Logged
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 Bob Wessner

  • "Carbs Suck!"
  • Really Old Timer ...
  • *******
  • Posts: 10,079
Re: Gas leak question
« Reply #10 on: October 08, 2007, 08:20:25 AM »
Johnnie, I must admit to being curious, particularly with a new seal and all.
Logged
We'll all be someone else's PO some day.
Pages: [1]   Go Up
« previous next »