Topic: CB550 Carbs

[cbtex]

Greetings, new guy here. Great site.  Quick question please...........recently purchased '78 CB550K and I'm thinking of doing some work to the carbs, do you need to separate the carbs to adjust/shim the needle jet?
Thanks.

[goldarrow]

Best way to work on carbs is to disassemble everything and clean them real good. But before that, download your manual. IIRC, there is a good tutorial for your specific carbs in the FAQ section. Read up and have fun with it.

[cbtex]

Thanks, so for future reference to adjust needle you have to split the carbs.

[goldarrow]

That's a nice looking K5. If it runs fine, I'd say just keep riding it.

[cbtex]

Oh ya, this '75 K5 runs great (only 7800 original miles), it was easy doing carb mods............I'm starting a winter project on a '78 CB550 and the carbs on this are a bit different that's why the question on the needle jets.

[totty]

On a CB550K3 and possibly others you can adjust the needle height with the carbs on the bike. It's fiddly but it's a lot quicker/easier than removing them to do it.

[chickenman_26]

I'm starting a winter project on a '78 CB550 and the carbs on this are a bit different that's why the question on the needle jets.

The jet needles on the '78 aren't adjustable, unless you shim them. But if you do that, the link plate may not screw down flush to the bottom of the slide. It shouldn't be necessary unless the jet/needle are worn out, but that isn't common with that style carb.
Stu 

[cbtex]

Thanks for the comments/info. Since I am going with pod filters and 4x1 MAC exhaust I thought the needle should be adjusted.  On the '75 CB750 pictured above I did this and it came out perfect.............but if you guys say it doesn't need it, guess I will give it a shot.

[cbtex]

One last question.  Does this look like the inside of 1978 CB550 carb, it doesn't look like the manual I have.
Thanks

[crazypj]

Carbs were changed on the 78 K, they are closer to CB650 carbs

[totty]

One last question.  Does this look like the inside of 1978 CB550 carb, it doesn't look like the manual I have.
Thanks

It looks the same as the carbs on my 79 550. The needles have the usual grove and clip system to set the height.

[cbtex]

No worries, finally figured it out.  Thanks to this great site and everyone's comments I found this exact carb assy in the Service Manuals listed here, it is under '77K Supplements.............too easy! 
Happy Holidays to all.

[chickenman_26]

No worries, finally figured it out.  Thanks to this great site and everyone's comments I found this exact carb assy in the Service Manuals listed here, it is under '77K Supplements.............too easy! 
Happy Holidays to all.

-The '77 carbs (X46A) needles have slots and an e-clip. The '78's (PD46C) do not. Also note the '77 float level is 14.5 mm. For '78, it's 12.5 mm. Bottom line - don't assume the info in the '77 supplement applies to the '78 as well. Have fun.

Stu

[brewsky]

My PD46C ('78 550K) have slots in the jet needles
My PD42B ('78 750K) do not

Don't forget to re-sync the carbs after changing the needle height