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Discussion Starter #1
Hello all,

I have a CB 175 that runs very rich. Mufflers, air filters etc are all stock and the carby is also all original. The bike has travelled 53,000 miles and I am running 88 main jets instead of 98's but still she runs rich.
So I am wondering if the jet needle is worn,and allowing too much fuel through.If the needle needs to be replaced,would the needle jet also be worn,and if so how is that replaced?


Thanks Graham
 

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Hello Graham, can you provide the year of your CB175 and the make of the carburetors? The factory specs I could find are for a 20mm bore, #95 main jet, #100 air jet, #35 slow jet. Is this correct for your carb?
 

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Discussion Starter #3
Hi Scramblr,

Its a 1969 k3 model with Keihin carbs.I have always understood the correct jets to be 38 pilot and 98 main.
 

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I found those specs on page 55 of the Honda Shop Manual (#6230401) for the 125 and 175 models. The CB175 main jet is #95, while the CL175 uses a #98. The CB175 slow jet is #35, and the CL175 has a #38.
My recommendation would be to replace the jets and needles as a set to know that are matched and within tolerances.
 

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Simo posted this a while back.

ID numbers are stamped on the flanges of the inlet manifolds.

jets.JPG
 

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Discussion Starter #6
Thanks for all your help,i am a little confused, I bought the bike in 1985 and the jets were 98 and 38, but I don't know if the PO had changed anything.My left carby flange is 306B whilst the right carb says 318B and the carb has 008A stamped on it.I remember that about 25 years ago I got another flange from the wreckers as I had overtightened the nuts,and cracked it.i wish now I had kept notes of work done to the bike.never mind it keeps me occupied in retirement.

Thanks, Graham
 

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At that kind of mileage the needle and needle jet are most likely worn. You will just be chasing your tail if you try to cure the problem changing main & pilot jets.
 

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Discussion Starter #8
Yes Mike that's what I am thinking too,i know I can replace the jet needle, but is the needle jet replaceable, and if so how.

Thanks Graham
 

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Depends on the carb, some of them are a push fit into the carb body they come right out with the main jet holder removed. A look at the new part should give you a clue as to how they go in.
 

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Discussion Starter #10
The only genuine honda jet needle I can find are from cmnsl and david silvers, but they are both far too expensive.I know its not recommended but I think I will give Keyster kits a go and keep my fingers crossed.
 
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