Honda Twins banner
1 - 12 of 12 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter · #1 ·
I pulled off the old gasket to replace it, and I noticed there is a disk behind the cap. I imagine this is part of a pressure relief mechanism. Does the gasket cover the gasket and this disk or does this disk sit out side of the gasket. I put the gasket over both. It it actually kind of a pain to put that sucker on when you cant get to the sides of the cap. Too bad the whole thing is riveted together so it cant be disassembled to be cleaned.


Does anyone have some insight?

Thanks

Steve
 

Attachments

·
Registered
Joined
·
27 Posts
Discussion Starter · #2 ·
OK, I am still getting the hang of posting photos. Yes that is the same pic three times.

Also, is that little notch in the cap a positive pressure vent? Any way to check if it is plugged? I tried blowing through it, but I got all that gas cap crud in my mouth and it does not taste good.

Steve
 

·
Premium Member
Joined
·
5,610 Posts
I removed the extra two photos for you.

As for the vent, yes, I believe that notch is the positive vent. Can that screw in the middle of the cap be removed? Looks to be a weird three-way head though. Other bikes I've had, you just take out that screw and you can clean the entire cap.
 

·
Registered
Joined
·
75 Posts
Try soaking the cap to remove the crud. Treat it with phosphoric acid, lemon, or vinegar. That center post either screws to its other half or is a press fit rivet.
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #5 ·
Perry, thanks for fixing the post.

The entire assembly is riveted together. The parts within the cap, the cap to the tank, and the latch are all riveted together. Removal or dissasembly would involve drilling out the rivets.

I am not sure how much pressure the vent is supposed to hold, but when I open the cap on in the sunshine it releases pressure. I wonder why I decided to replace the gasket then?
 

·
Registered
Joined
·
133 Posts
I just did this job on a CB360. The rivit you see did not go through to the chrome cap. If you look along side the spring disk you should see there are 4 pointed pieces of spring steel that hold the cap center into the chrome outer. I dripped a bit of oil at each of them, then worked a skinny screw driver under the spring disk as far in toward the chrome cap underside as I could, and gently pried the whole thing out. It took a little prying and working in two directions and it came loose and the whole thing popped out.

Be sure you cover the tank and the opening with protective materials, because when it came out it went bouncing across the tank to the garage floor.

Pushing it back in was very easy. If it looks a little bent from your prying, straighten it before putting it back.
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #7 ·
Wentwest,

Thanks for the tip. It just popped right out and I was ready to catch it. I cleaned the parts up with some brake cleaner and then with Bar Keepers Friend. It tastes much better now.

Now I need to figure out where that flat disk goes with respect to the gasket. Inside of the gasket or out. How did you put yours together?

Thanks,

Steve
 

Attachments

·
Registered
Joined
·
100 Posts
I have the exact same question, this is the only thread I could find and it's been unanswered since 2011! gah!

The free spinning 'flat disk' plate goes inside the seal, (as pictured) right? Anyone?

IMG_3028.JPG
 

·
Premium Member
Joined
·
2,838 Posts
The gasket can be changed without taking it apart, you need to get the 2 discs inside the gasket. I'll see if I can get pics later. It isn't easy but not too bad with patience. I did my 450K6 and 500T.

Just to clarify something in this thread, if your tank hisses when you open it, the gasket is not the problem, the vent is. If bad, the gasket will let fuel slosh out onto your tank, and leg, and crotch, seat, etc.
 

·
Registered
Joined
·
100 Posts
The gasket can be changed without taking it apart,
I'm not sure why you'd bother though? It's so simple to leverage the entire unit out. I've watched youtube videos of people trying yo replace the seal without removing mechanism from the cap it and it looks excruciating.

Thanks for the info about the disk. I've installed the new seal now and it's all back in place. I decided to replace mine because the old seal was crusty and cracked. I just added the $2 new seal on a whim to an larger order from an online store. Money well spent. :)

Thanks Jim.
 

·
Registered
Joined
·
384 Posts
Not sure if my 74 CB has the same gas cap, but I replaced the gasket without taking the cap apart. It was a zen like experience ;)
Seriously though just equal measures patience, persistence and dexterity and it was good to go.
 
1 - 12 of 12 Posts
Top