Author Topic: CB550 Jetting questions with 4in1 exhaust  (Read 1053 times)

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Offline jacksonsk

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CB550 Jetting questions with 4in1 exhaust
« on: April 25, 2020, 06:21:33 pm »
Kept the stock air filter and running a delkavic megaphone 4into1 exhaust. Running lean.
Carbs are stock jets, Was wondering if anyone has input on which jets they are using with their 4in1 with baffle in? I would love to find a place to start. thank you! 8)

Offline Pielz

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #1 on: April 25, 2020, 06:55:15 pm »
Delkevic, at least on my 750, specifically said that I didn't need to re-jet. And I didn't!

Sorry I just saw that you said you were running lean. I guess that makes my response pretty unhelpful huh? Lol
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« Last Edit: April 25, 2020, 07:12:15 pm by Pielz »

Offline jayrdee

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #2 on: April 25, 2020, 07:13:08 pm »
I just installed a Delkevic 4-1 on my CB750 (and I took the baffle out), went two sizes higher on my main jets, and lowered the needle clip to the middle position. It was originally in the top/lean position.

Was it necessary?  Probably not, but the but dyno feels a difference Lol.
[I have no idea what I'm doing]

Offline jc914

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #3 on: April 29, 2020, 08:45:55 am »
Try 110 main jets for a start.
1974 CB550K0

Offline steeldoncb550

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #4 on: April 29, 2020, 09:34:38 am »
110’s will be too much for only the exhaust. Start at 100’s.

Offline Bankerdanny

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #5 on: April 29, 2020, 09:49:02 am »
What year and model 550?
"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 jc914

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #6 on: April 29, 2020, 10:14:51 am »
@steeldoncb550,  74-76 (CB550K) stock main jets are#100.  75-77 (CB550F) is #98. 

https://www.sohc4.net/cb550-faq/indexphp/cb500550-carb-specs
1974 CB550K0

Offline jacksonsk

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #7 on: April 30, 2020, 05:15:32 pm »

Offline calj737

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Re: CB550 Jetting questions with 4in1 exhaust
« Reply #8 on: April 30, 2020, 06:28:58 pm »
105s maximum. you should also check the needle clip position. With stock jets, simply moving the needle a clip richer might be easiest and best remedy.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

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