CB 550 K3 carbs

[chrisr58]

I have asked this question elsewhere, but this may be the right place. Can anyone tell me what are the best carbs I can look for to go on my 1977 550 K3, we can’t get the PDs to idle or run smoothly on no 2 and I understand there is a better alternative. (Or is there someone who can suggest a fix for the PDs?)
Thanks
PS. The info I’ve been given is “it’s the very fine fixed idle circuit that seems to be blocked, I can’t get in there as the jets are pressed in. Tried air, ultrasound and solvents”

[Bryanj]

You can remove the pilot jets by gripping with parallel jaw pliers(yes they are different) or carefully with mole grips and twist n pull at same time. Refit with a tap from a nylon hammer

[peterengland]

Had problems with my PD carbs a while back but found that a bristle from a wire brush cleaned all the jets really well, not had a problem since

[Bryanj]

I hate, loathe, detest, swear at and dont work on pd carbs any more BUT with a lot of patience and an ultrasonic cleaner plus a delicate touch(specialy on pilot screws) they can be made to work well but when working run the engine every week for a reasonable time.
The tiny washers and O rings on the pilots are critical as well.
Pilots,O rings andwashers can be got from  Sirius Consolodated in Canada

[keithtraffic]

So, I have PD carbs on my 1979 550K3 and they have caused a lot of heartache over the last couple of years, but gave then a long ultrasonic clean (no 2 needed two cleans!) AND replaced all the jets etc AND took great care to set them up properly. With a static balancing the bike seemed to go OK but would not really tick over at anything less than about 1800 revs, but I also went to the trouble of doing a proper balancing job across all 4 carbs with the requisite vacuum gauges - although this resulted in what seemed only very minor changes to the setup, the difference in performance was quite noticeable and the bike also now ticks over evenly at between 1200 and 1400 revs. I am just hoping that after the winter (when the bike wont be used much) I don't find myself back at square 1!

[deltarider]

I have worked on a K3 where a true 1000 RPM  was shown as 1400 RPM on the onboard ND tacho... So be careful if you 're trying to arrive at an '1000 RPM' idle.

[Piki]

Best option is fit a 550 F carbs on your 550 K3, PD carbas are a nightmare.

[deltarider]

[...] 550 K3, PD carbas are a nightmare.

Yes, but is mainly due to changed fuel properties. Either ride regularly or add some (= socalled maintenance dose) fuel system cleaner like Redex or a similar product.