Topic: What tanks will fit my 75 550K1

[lone*X]

Looks like I need a replacement tank for my 75 550K1 project.  I would prefer to keep it early with the flip up gas cap but would go with the later enclosed cap type if it were clean enough inside.  Search didn't work so well so I pose the question.  What years and or models of tank will fit a 550K1? 

[TwoTired]

Any CB500 71-73  Cb550 K0 74.  But, the petcock is a different style.  Works fine, though.
Direct swap would be a 75 or 76 CB550 petcock and all.

All the F model (door) tanks 75-77, will fit onto the frame, as will the 77-78 (door) tanks.  However, they are longer and require a seat length change.  The last two years of CB550 (77-78) production used a single outlet petcock with a T fitting to feed the carbs of the 77 F model  (the K model carb only had on feed nipple.)

Cheers,

[lone*X]

Thanks TwoTired, this is what I was looking for.  One more question.  Is the tank bung thread size the same on the 500 and K0 tanks as it is on the K1?  I rebuilt my petcock before the bike got set up and I believe it is still usable.

[TwoTired]

Is the tank bung thread size the same on the 500 and K0 tanks as it is on the K1? 

Nope, as I said, those petcocks are different.    There is no bung on the earlier tanks.  Just a hole and two screw threads to attach the petcock.

Cheers,