Author Topic: CB550 Keihin PD46C Carb needle adjustment  (Read 5818 times)

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someguy

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CB550 Keihin PD46C Carb needle adjustment
« on: December 04, 2009, 06:18:07 AM »
I'm rebuilding/cleaning the carbs from a 1978 Cb550K. The bike came with pod air filters when I bought it, so I (presumably) need to enrichen the mixture a bit. I've set the pilot air screw out 1 turn (as opposed to the recommended 1.5), and I'm cleaning the jets as we speak. My question is in regards to the needle clip position. It seems that moving the clip a position or two richer would be just what this bike needs.

Is there a way to change the needle clip position without completely disassembling the carbs? In other words, is there a way to get the throttle slide linkages out without separating the carbs, disengaging the throttle and choke springs, etc? I actually disassembled everything last night and it didnt seem possible, on the other hand, it seems like people often fiddle with this position, and I cant imagine that they completely disassemble everything to do so each time.

A final question: I'm not really interested in getting extra performance from the pod filters - I'd rather have the bike run well. Is there a way to (elegantly) restrict the pods (perhaps some kind of additional filter inside?) so I can run stock jetting? Thanks in advance for your help!

Offline edbikerii

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Re: CB550 Keihin PD46C Carb needle adjustment
« Reply #1 on: December 04, 2009, 09:26:13 AM »
Sorry, you can't get the bike to run well with pod filters without the extra performance.  You must take the good with the bad. :)

Look at the two links in my sig for just the solutions you need.
SOHC4 #289
1977 CB550K - SOLD
1997 YAMAHA XJ600S - SOLD
1986 GL1200I - SOLD
2004 BMW R1150R

Jetting: http://forums.sohc4.net/index.php?topic=20869.msg258435#msg258435
Needles:  http://forums.sohc4.net/index.php?topic=20869.msg253711#msg253711

Offline free85

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Re: CB550 Keihin PD46C Carb needle adjustment
« Reply #2 on: July 19, 2013, 09:12:49 AM »
I hate to resurrect the dead (well, no I really don't)... and while I'm not putting pods on my '78 CB550K just yet - Thank you for when I do!

Offline ANDY W

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Re: CB550 Keihin PD46C Carb needle adjustment
« Reply #3 on: July 19, 2013, 10:00:13 AM »
"I've set the pilot air screw out 1 turn (as opposed to the recommended 1.5)"
those carbs have a idle mixture screw, which adds fuel not air, so u need to turn them out more not in. i would probably start at 3 turns out

Offline uksparky

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Re: CB550 Keihin PD46C Carb needle adjustment
« Reply #4 on: July 19, 2013, 10:19:23 PM »
Yes 3 turns out  for lean...got the pods/stock exhaust...needles jets can be removed ...remove the two screws carb top cover/large phillips on throttle shaft....look down see the two phillips screws...take em out....lift up lever ...needle nosed plyers lift needle out...set my carbs to 4th from top on needle jet...runs ok
Present bike 1982 900C Custom