gas tank differences 1979 - 1980 550E

[jimg]

This is what a 80' petcock should look like.

That isn't what mine looks like. On mine the fuel line comes straight out of the back at the bottom and the vacuum line comes out up higher and points forward.

I'm going to try and get my camera working and show some pictures.

[jimg]

The 80 definitely won't work, you can't tighten the bolts, if you do you would probably crack the body of the valve.

The bolt pattern is the same between the two valve, but they fit the tank differently.

On the 79 petcock, the other think I had to do was trim the end of the lever off because it hit the top of the carb. (mine now ends at the circle).

I'm going to have to take my tank off. Looking underneath it, I think I see what you mean. It looks like the 80 tank is just a bit more narrow where the petcock is and will let the vacuum module clear it.

Like you said you would have to dimple the 79 tank to get it to clear. I need to sync my carbs so I'll pull the tank and verify that.

[jimg]

Here is the best photo of the 79 tank.



Here is the best photo to see the difference in mounting on the 80 tank



And here is a good photo of the 80 petcock



8trackmind - my 1980 GS550ET petcock doesn't look like yours!