SOHC.co.uk Forums > CB500/550

The actual fuel hight in these 550 K3 Carbs

<< < (4/4)

nairb:
So I seem to have the PD46AC......... which is different to the PD46AA

When I rebuilt the carbs2-3 years ago I used a spare float... it turns out it was a float from a pd46AA.

Which has a float level of 12.5 instead of 14.5.  Here is a nice pic showing the two side by side

[ Guests cannot view attachments ]

One has "K" marked on(pd46aa) and the other not.

I can put the old one back in  (no "K").   

Might even explain why 3 carbs seemed to be ok and one not.

deltarider:
In the past I've tried to find out which K3 carbs had the 14,5mm and which had 12,5mm float levels. Alas, I haven't found trustworthy sources. The one shown here is dubious, because it is by an American who thinks mentioning the 'year' is good enough. When in doubt, I'd opt for the 12,5mm level as 14,4 could result in a too lean mxture.
Can you shoot a picture of the front opening (exit so to speak) of your airfilter element? There have been differences there too: wider/smaller, but I don't know it is somehow related.

nairb:
Yes, the air filter.  I purchased a new "Pattern" one that said it was for a cb550K3.  Fitted it and the bike performance was worse.  Quite a bit worse.  So I put the old dirty one back in.  The old one must have been purchased a few years ago.
Here is a pic of the two.

[ Guests cannot view attachments ]

Maybe there are different type of filter depending on the carb type.....pd46aa or pd46ac

deltarider:
Makes me wonder what dimension the corresponding opening in the CHAMBER has. Have you checked?

scottly:

--- Quote from: nairb on May 20, 2026, 03:50:03 AM ---I have been trying to find if Honda ever said what the fuel height should be in the carbs of a CB550 K3.

Honda does say how far the float should dangle down ....  22mm I think.

But on my KZ750 twin I use a clear tube stuck in the bottom of the carb bowl and this gives the actual fuel height, As shown in the pic below.

(Attachment Link)

And Kawasaki says what the fuel level lines up with.  All very helpful.

Does anybody know if honda ever did this for the 550 K3.  I now need to check the float heights .... It would be interesting to try this with the carbs still on the bike.

Ta
Nairb

--- End quote ---
The fuel level with the clear tube should be about 3mm below the top of the bowl.

Navigation

[0] Message Index

[*] Previous page