Topic: PD carb differences??

[wannabridin]

hey guys.  i recently purchased a set of PD carbs, and when comparing them to my own for parts i could maybe use, i noticed there was an extra line on the ones i bought.  mine doesn't have it, as evidenced by the pictures below.  any clue what this is for?  it's not like mine are missing, there isn't even a hole or a plug in mine.  the lines are in between all carbs, and there's a port visible next to the line.  thoughts?

[Trav-i]

Hey Garrett,

That line is just a breather.  I have that line on my F3 and it just goes to atmosphere.  Plus all the K bikes had them too.  I don't believe it's anything to worry about.

Travis

[wannabridin]

awesome.  thanks for the input!  i figured it was some sort of equalizer, i just wanted to make sure.

[db22]

My 1975 CB550 has PD carbs that some PO fitted.  Having throttle cable fit issues. Engine starts and runs fine, but I wonder why the PO fit these carbs.  Anyone know what year PD carbs were factory-fit on 550 engines?

[bollingball]

http://www.sohc4.net/index.php/archives/230 db22 look here. When doing a search start at the home page for more results. I don't know much about 550's I have a 750K8 PD's were 77&78 for them.

[Kong]

My 1975 CB550 has PD carbs that some PO fitted.  Having throttle cable fit issues. Engine starts and runs fine, but I wonder why the PO fit these carbs.  Anyone know what year PD carbs were factory-fit on 550 engines?

The cars in your picture have two screws holding the tops in place, one each, fore and aft.  Those carbs (PD46) were used in 1977 (46a) and 1978 (46c).  Earlier carbs had top mount screws opposing each other latterly.   Differences that I now of between the 'c' and 'a' models, and there are certainly more that I don't know about, are different sized jets, different fuel delivery scheme, and different float-bowl-vents.