Topic: Vacuum synchronizing pd46c 78 cb550

[evopgt]

Going to be doing this tomorrow!  My ? Is.... I understand the slide adjustments are under the top carb covers,  so I need to remove all 4 covers ?? Then start the bike and make my adjustments as I need to?? Won't the covers being off the carbs throw off the airflow/ vacuum readings  in the carbs??

[Can550]

Good to see this topic as I have done mine little earlier but not sure if I did right. Would like to see/ hear what experts have to say
All the best


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[uksparky]

I did my sync by putting block of wood under rear of tank, yes the carb tops have to come off, one of them you can not adjust  #3......this is your reference point, I used carbtune ..plus a fan in front of engine...the top covers don't effect the sync

[Deltarider]

one of them you can not adjust  #3......this is your reference point

It's #2 actually.

[evopgt]

My non adjustable carb is #1. 

[Killer Canary]

All of mine are adjustable.

[Stev-o]

I prefer to take the tank off and use an aux tank, gives you more room to work on carbs.   
It's really a basic task, dont sweat it.

[evopgt]

Yeah, I was planning on setting the tank on a table beside the bike, where I can still operate the petcock, throttle and main idle screw from the throttle side of the bike.. I ll have to run a temporary 2 foot fuel line to do this. Thanks for the info

[Johnie]

Just did my 78 CB550K. Carb #2 was the slave on mine. Maybe someone rebuilt the carbs and put the guts from #2 into #1? Be sure to put a fan on the motor. I used an auxiliary tank on mine which you will see in the pic below. I used 2 fans as it keeps me cool too

[Bankerdanny]

All of mine are adjustable.

I believe that only the 77-78 550K bikes with the PD series carbs have the one carb with the fixed slide.

[Can550]

All of mine are adjustable.

I believe that only the 77-78 550K bikes with the PD series carbs have the one carb with the fixed slide.

Yes only 1977-78
My 74 and 76 all could be adjusted which seemed harder than one with reference carb


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[Killer Canary]

The Canary is a '78 with PD46s.

[DaveBarbier]

Yeah, #2 should be the non adjustable carb. I guess it's ok if someone swapped the slide innards, though. And no, having the tops of the carbs off is fine. Just have the top of the non adjustable carb off also.


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[TwoTired]

The Canary is a '78 with PD46s.

And you are certain the carbs are in the same stock configuration as when new?

Funny that the shop manual supplements refer to #2 as the nonadjustable carb for the pd carb sets.

Cheers,

[Killer Canary]

I'm fairly certain that I was the first into the carbs 14 years ago.
There was yellow paint on the adjuster screws and nuts.
Could've been replaced without disturbing that though.
Maybe a Canadian thing.

[evopgt]

Well, I got the carbs all synced after putting everything in the carbs back to stock except the main jet, which is now a 95 from a 90. Still has a little much hiccupping and popping for my liking.  I may raise the needles again.  It ran better that way. I got the guage needles to all fluctuate in the same areas for all 4 cylinders. But I'm concerned where they are fluctuating on the gauges. They don't fluctuate in the area that is described as a normal healthy motor on the guage faces.  Does this matter??

Check the video here

[Deltarider]

They don't fluctuate in the area that is described as a normal healthy motor on the guage faces. Does this matter??

No. It looks to me your set is just four times an ordinary vacuum meter with a scale designed for one carb cars. I suggest to dampen 1, 2 and 3 a bit more as you did #4. I know, it's a kind of tricky.