Petcock and Gas Cap

[hogtyed]

I recently purchased a 79 Special II. It had 3/4 of a tank of gas sitting in it since '93. I have went through both carbs and they are cleaned and rebuilt. I'm now working on the fuel tank. The petcock looks a bit worse for the wear. It's a bit rough and I don't think a rebuild is in it's future. Where would be the best place to purchase a new one?

Next on the list is my gas cap. I need a new seal for it. It was brittle and I had to cut it off. I need to purchase one if these, too. Best spot...dealer or elsewhere? Also, I would like to completely disassemble the cap. I have removed the three screws, but it does not come apart. Any help to taking the cap apart without destroying it would be highly appreciated.

Thanks in advance..

 

[Royboy]

Lots of places supply parts for the XS650. Some offer great OEM stuff and others often sell Asian clones that may or may not be OK. Personally I like:

http://www.boats.net/parts/search/Yamaha/Motorcycle/1979/XS650SF/parts.html

Didn't see your gas cap gasket there but your local Yamaha dealer should have it.

roy

 

[fredintoon]

Next on the list is my gas cap. I need a new seal for it. It was brittle and I had to cut it off. I need to purchase one if these, too. Best spot...dealer or elsewhere? Also, I would like to completely disassemble the cap. I have removed the three screws, but it does not come apart. Any help to taking the cap apart without destroying it would be highly appreciated.

Hi hogtied,
those 3 screws are a snare and a delusion, all they do is hold the rubber thing's gas vent parts together.
To get the rubber thing off you'll need to remove the lock as you already have then flip the cap's inner workings out of the chrome cover,
it may take a little prying but it'll hinge up and over at the attachment bolt end.
Then you will see the other side of the rubber and how it's held on by a central E-ring in a shallow depression.
Pry the E-ring off and it all comes apart.

 

[gracer]

Check to make sure your gas cap vents. I put a new seal on and didn't check the vent in the cap. Sure enough I got a vacuum going in the tank and engine bogged down and didn't finish the ride all because I had an air-tight seal. I like my MikesXS seal - FYI.