Topic: 550K vs. 550F Gas Tank

[pwright]

Greetings,

I need a new tank for my '78 550K, as the old one has holes and I want to get on the road ASAP. I know the earlier 550 tanks were shorter than the 77/78 550K tanks, so that won't work. However, is the 77/78 550F tank longer than the 550K tank? They look very similar... any help or anybody with a spare tank for relatively cheap would be appreciated.

Thanks,
-Pat-

[Chris Liston]

Although the 550F tanks look the same as 77-78K tanks they are not.  They have different bung for the petcock.  The F models used the larger 2 outlet petcock and the K the smaller single outlet unit.  The mounting bung onthe F's is a larger diameter.  But if you get a F petcock with the tank you can run 2 lines to your carb banks.

[pwright]

Thanks Chris,

Do you know anything about the lengths of the two? Are they dimensionally similar? Reason I ask is that I've seen some F tanks for sale in my price range, but I have a nice newly recovered seat (on there when I bought it), and don't want to have to change the seat to use the tank. So... any length comparisons?

Later,
-Pat-

[Chris Liston]

I think (THINK) the F and 77-78K tanks are the same size.  I had bought a K tank a few years ago and it was the same as my F.  Thats the reason I know the petcock bungs are different., back to ebay it went

[bwaller]

The two tanks are the same size and like Chris said the bung is smaller on the K tank for a single outlet petcock.