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Author Topic: Honda CB750k2 main jets  (Read 1967 times)

Offline Pauarc

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Honda CB750k2 main jets
« on: July 31, 2023, 03:20:17 PM »
I have been reading up on the main carb jet for my bike they have been fitted with 120
When looking at info I think it should have 110 the carb are 657b all the plugs are on the rich side could this be the course.The float are set at 26mm slow jets 40 air screw 1and1/2 standard air filter HM341 exhaust Middle slot on needle
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Trigger

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Re: Honda CB750k2 main jets
« Reply #1 on: July 31, 2023, 07:39:07 PM »
All my CB750 K2's 1972, 1973, have had 657A carbs with 110 main and 40 slow. Yours is a later K2 so, 657B carbs are the original ones  ;)
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Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #2 on: August 01, 2023, 07:30:46 AM »
Why would someone fit 120 when they should be 110 I have now fitted 110 but have not been for run yet
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Trigger

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Re: Honda CB750k2 main jets
« Reply #3 on: August 01, 2023, 07:53:07 AM »
Maybe some one changed the needle's to suit a 120 jet. I had K271307 needles with 110 jets and it had trouble on tick over.
Changed to K27201 and it ran fine  ;)
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Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #4 on: August 01, 2023, 12:15:17 PM »
I didn’t think the needle would effect the tick over all I no they’re on middle slots it rev from tick over ok sits at about 1000 to 1100 will have to see what its like when I get out for a run
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Martin6

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Re: Honda CB750k2 main jets
« Reply #5 on: August 01, 2023, 05:05:45 PM »
Found this useful, may need to paste the address into your browser, as it wont paste as a URL. Shows the combinations of Honda carbs, by model / year with float heights, jet sizes and needles:
content://com.sec.android.app.sbrowser/readinglist/0801085831.mhtml
👍
« Last Edit: August 01, 2023, 05:10:19 PM by Martin6 »
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Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #6 on: August 01, 2023, 05:14:07 PM »
Can’t open link
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Martin6

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Re: Honda CB750k2 main jets
« Reply #7 on: August 01, 2023, 10:46:00 PM »
Just copy it and paste it into your Internet browser.
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Offline Trigger

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Re: Honda CB750k2 main jets
« Reply #8 on: August 02, 2023, 08:18:21 AM »
I tried a copy and paste. Doesn't take me anywhere.
This is for USA Bikes >> http://www.hondachopper.com/garage/carb_specs/carb_specs.html
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Offline Martin6

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Re: Honda CB750k2 main jets
« Reply #9 on: August 02, 2023, 08:51:27 AM »
Strange, still works for me. Don't know how to fix it.
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Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #10 on: August 02, 2023, 12:04:37 PM »
Found this info my air screws have the holes in end
« Last Edit: August 02, 2023, 12:08:39 PM by Pauarc »
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #11 on: August 02, 2023, 12:06:29 PM »
This as well
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Trigger

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Re: Honda CB750k2 main jets
« Reply #12 on: August 02, 2023, 02:29:06 PM »
Quote from: Pauarc on August 02, 2023, 12:04:37 PM
Found this info my air screws have the holes in end

There is a difference between the USA market on carbs and the UK. The USA kept dropping sizes as they had the problem with USA regulations on emissions. UK K2's run on 110 main jets.
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Offline Pauarc

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Re: Honda CB750k2 main jets
« Reply #13 on: August 02, 2023, 04:11:23 PM »
Is there a good place to look for uk info and specs on uk bikes
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Honda 90ss, Cb250k1 supper sport,
Cb400 four, CB750k7, Cb550, Cb750f2n,
Cb750k2

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: Honda CB750k2 main jets
« Reply #14 on: August 02, 2023, 04:26:01 PM »
Quote from: Pauarc on August 02, 2023, 04:11:23 PM
Is there a good place to look for uk info and specs on uk bikes
Unfortunately not.
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