Author Topic: Cb550K 1978 Needle adjustment  (Read 189 times)

Offline Phteix

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Cb550K 1978 Needle adjustment
« on: April 04, 2021, 11:58:13 PM »
Happy Easter everyone.

I'm trying to do some tunning on my carb, but I can't get the needle out. Do you have any idea how to reach the needle on this carb (see image)? I know that the arm-looking thing needs to come up removing the first bolt, and then? I tried to slide the part that connects together but did not work (red in the picture)...

Any tips would be very appreciated.
Cheers.

Offline Bryanj

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Re: Cb550K 1978 Needle adjustment
« Reply #1 on: April 05, 2021, 12:51:36 AM »
Those are PD carbs and orrible to work on. I think you have to work on all 4 at once

Offline deltarider

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Re: Cb550K 1978 Needle adjustment
« Reply #2 on: April 05, 2021, 07:27:29 AM »
I don't know what issue you're trying to cure. Me personally, I'd leave them alone. The effect will be little. Seen that you run pods, I'd concentrate on the main jets. Are the slow jets OK?

Online K2-K6

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Re: Cb550K 1978 Needle adjustment
« Reply #3 on: April 05, 2021, 12:03:17 PM »
I don't think you want to remove that pin.

Look down into the top of the slide and there are two screws, undo them on all carbs and you may  e able to turn the lift mechanism fully out of the way to get the needles.

Are you adjusting for pods?

Offline deltarider

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Re: Cb550K 1978 Needle adjustment
« Reply #4 on: April 05, 2021, 12:31:10 PM »
I don't think you want to remove that pin.

Look down into the top of the slide and there are two screws, undo them on all carbs and you may  e able to turn the lift mechanism fully out of the way to get the needles.

Are you adjusting for pods?
If your screws have been as firmly fastened (assembly) as in the predecessors of your carbs, be prepared. You will ab-so-lute-ly need a JIS screwdiver to unscrew and not ruin their heads.

Offline robvangulik

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Re: Cb550K 1978 Needle adjustment
« Reply #5 on: April 05, 2021, 12:37:04 PM »
I don't think you want to remove that pin.

Look down into the top of the slide and there are two screws, undo them on all carbs and you may  e able to turn the lift mechanism fully out of the way to get the needles.

Are you adjusting for pods?
And definitely use a real JIS screwdriver for those small screws, or you'll only be able to use those screws once!

Offline robvangulik

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Re: Cb550K 1978 Needle adjustment
« Reply #6 on: April 05, 2021, 12:39:49 PM »
Well Delta, it seems for once we agree on something....

Offline Phteix

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Re: Cb550K 1978 Needle adjustment
« Reply #7 on: April 05, 2021, 08:43:53 PM »
I don't think you want to remove that pin.

Look down into the top of the slide and there are two screws, undo them on all carbs and you may  e able to turn the lift mechanism fully out of the way to get the needles.

Are you adjusting for pods?

OOOOK! I better do not touch that screw and needle yet :P

I'm just trying to adjust everything to the pods, I know it will never be perfect, I don't really care about the look, but that's the way I bought the bike, would love to have the original filters.

I run at the moment with #90 Main and #42 Slow, and I have #100 and #110 main, and #40 slow on the way from 4into1. I Will see how it goes, I have a 4into4 exhaust, any tips on the jetting?

Tnks.

Online K2-K6

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Re: Cb550K 1978 Needle adjustment
« Reply #8 on: April 05, 2021, 09:23:42 PM »
If you want to experiment a little to get it to cope with the pods,  you could try running with both R type spark plugs and R type plug caps in NGK 8 heat range.

It works better in burning more lean mixtures that non airbox intake makes. Also set the air screws for idle at 3/4 turns out for starting point. Then assess if the running improves at all.

Offline Bryanj

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Re: Cb550K 1978 Needle adjustment
« Reply #9 on: April 05, 2021, 09:50:02 PM »
The problem you have is the pd carbs were designed for the californian emmision regs and run lean to start with lus were designed not to be alterable, hence the press in pilot jets and very fragile mixture screws. If you want to keep the pods it may well be worth fitting the earlier 550 carbs or even 500 ones as they have easier to get jets

 

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