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Author Topic: cb500 vscb550 carbs  (Read 824 times)

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Offline 1stgenxxx

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cb500 vscb550 carbs
« on: May 19, 2014, 07:42:38 AM »
What are the differences between the cb500 and cb550 carbs?
I'm putting together a cb500 but dont have a good set of carbs...seems 550 carbs are a lot cheaper and easier to aquire. I'm going to have to play with the jetting anyway due to air box and exhaust changes.
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Offline Bankerdanny

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Re: cb500 vscb550 carbs
« Reply #1 on: May 19, 2014, 08:05:30 AM »
Two Tired will weigh in on this I'm sure. But I am pretty sure you can use 74-76 550K and all year 550F carbs without any issues, although as you say you will need to adjust the jetting.
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"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline TwoTired

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Re: cb500 vscb550 carbs
« Reply #2 on: May 19, 2014, 11:06:22 AM »
The carb bodies for 627B (cb500), 022A and 087A (Cb550K), and 069A (cb550F) are all the same casting with different internal parts (jetting).
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline 1stgenxxx

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Re: cb500 vscb550 carbs
« Reply #3 on: May 19, 2014, 11:58:11 AM »
Quote from: TwoTired on May 19, 2014, 11:06:22 AM
The carb bodies for 627B (cb500), 022A and 087A (Cb550K), and 069A (cb550F) are all the same casting with different internal parts (jetting).
Thats what I was thinking. looks like I will be going with the 550 carbs
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Offline Kenzo1979

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Re: cb500 vscb550 carbs
« Reply #4 on: May 19, 2014, 01:07:34 PM »
This is an interesting post to me because I have a K0 500 and a K0 550 that both have the 022A model carbs on them.  I know the 550 was completely stock when I bought it, but the 500 definitely had it's carbs changed at some point.  Could someone in this thread say what the proper jetting would be for 022A carbs on a 500?  Not trying to jack the thread, but it does seem relevant to your original question.
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--Kenzo
** 71 CB500, 74 CB550, 76 CB400F, 77 CJ360t **

Offline Bankerdanny

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Re: cb500 vscb550 carbs
« Reply #5 on: May 19, 2014, 01:59:51 PM »
The jetting should be whatever the book says it should be for a stock 500. The jets and needles are interchangeable between the carbs.
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"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline Kenzo1979

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Re: cb500 vscb550 carbs
« Reply #6 on: May 19, 2014, 02:03:44 PM »
Gotcha, stock jetting in the non-stock carbs, cool.
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--Kenzo
** 71 CB500, 74 CB550, 76 CB400F, 77 CJ360t **

Offline Kenzo1979

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Re: cb500 vscb550 carbs
« Reply #7 on: May 19, 2014, 02:13:29 PM »
After searching the forum, it seems that the jetting is the same anyway;  100 mains and 38/40 slow.  That makes me feel better.
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--Kenzo
** 71 CB500, 74 CB550, 76 CB400F, 77 CJ360t **

Offline TwoTired

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Re: cb500 vscb550 carbs
« Reply #8 on: May 19, 2014, 02:19:31 PM »
Quote from: Kenzo1979 on May 19, 2014, 02:13:29 PM
After searching the forum, it seems that the jetting is the same anyway;  100 mains and 38/40 slow.  That makes me feel better.

No, it isn't the same.  "Jetting" includes the slide needle size, taper, and position.  And, #38 is different from #40.

But, I guess it is all the same if "running" means the same as "running well".
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Kenzo1979

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Re: cb500 vscb550 carbs
« Reply #9 on: May 19, 2014, 02:26:04 PM »
Yeah, you're right.  I wish This was posted 2 months ago when I had both sets of carbs pulled.  But I will be investigating this closely the next time I pull the 500 carbs.  Thanks for the insight. 
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--Kenzo
** 71 CB500, 74 CB550, 76 CB400F, 77 CJ360t **
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