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Author Topic: 77 Carb Jets  (Read 2039 times)

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Offline 77 CB750A

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77 Carb Jets
« on: August 31, 2011, 08:42:18 PM »
Does anyone know what is the stock jet size for a 77 750a carb?
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Offline raymond10078

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Re: 77 Carb Jets
« Reply #1 on: September 01, 2011, 05:46:23 AM »
Main - 108
Slow - 38
Air - 200
Slow Air - 150

By the way - this site has the service manual for download.  That document is the source of this info (page 1-2).
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1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

Offline dtmmil

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Re: 77 Carb Jets
« Reply #2 on: September 02, 2011, 12:31:53 PM »
I may have a set of 108s if you need, pm me if you do.
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Offline 77 CB750A

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Re: 77 Carb Jets
« Reply #3 on: September 06, 2011, 07:26:58 PM »
I converted my exhaust to an open pipe and just need to figure out what jets to order. The guy I am working with said stock plus 2 sizes. Guess I will need 115 and 120s. Not sure they make 118?
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Offline dtmmil

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Re: 77 Carb Jets
« Reply #4 on: September 07, 2011, 02:58:07 AM »
I have a set of 115s also, and I believe they make a 117.5. You may or may not need to go much bigger then stock, you will have to run it and see. I have heard of several people swapping to the K/F style roundtop carbs and getting much better performance then the stock A carbs.
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Offline raymond10078

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Re: 77 Carb Jets
« Reply #5 on: September 07, 2011, 06:12:10 AM »
A 108 plus two sizes is a 112.

99101-GHB-1080 (is a 108)
99101-GHB-1120 (is a 112)

Sizes - 108, 110, 112, 115, 118, 120, etc.
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1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

Offline dtmmil

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Re: 77 Carb Jets
« Reply #6 on: September 07, 2011, 07:06:43 AM »
Do they go in 2s or 2.5s, either way, if you need a set of 115s let me know, I may have a set of 110s also, would have to check.
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Offline raymond10078

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Re: 77 Carb Jets
« Reply #7 on: September 07, 2011, 09:48:42 AM »
Usually, from what I've seen in the past, the jets are sized by 2's and 3's.

110 + 2 = 112
next size is 112 + 3 = 115
next size is 115 + 3 = 118
next size is 118 + 2 + 120.

Don't know why - just what I've seen.
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1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.
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