Author Topic: CB175 running problem  (Read 144 times)

Offline RGP750

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CB175 running problem
« on: May 21, 2019, 06:26:16 PM »
Hi All
Finally totally finished the 175 with loads of NOS parts including Carbs.
Problem, is starts and runs nicely on tick over on choke ,turn off choke
and the engine splutters and pops and dies when throttle is opened HELP!!!
checked all jets ,fuel supply and played with carb settings all to no avail.
Met Kettle (Mick on here at a jumble on Sunday and he suggested adv and ret, checked and seems ok)
I'm stuck
Rich
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Online K2-K6

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Re: CB175 running problem
« Reply #1 on: May 21, 2019, 07:06:52 PM »
Try putting a rag over the airbox intake as you take off choke,  just to see if it improves as it would make it richer and give you more assessment.

In other words,  does that make it better or worse?

Offline petermigreen

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Re: CB175 running problem
« Reply #2 on: May 21, 2019, 08:04:41 PM »
Strangely just had this problem on my 2T DT175
Solved by replacing the spark plug.
Just saying.
1928 Ford Model A Tudor Sedan
1942 Ford GPW Jeep
1944 42WLA
1972 CB750K2 USA Candy Gold
1972 CB500K2 USA Candy Jet Green
1976 DT175C
1982 RD200F

Offline RGP750

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Re: CB175 running problem
« Reply #3 on: May 21, 2019, 09:20:46 PM »
Thanks Guys. I'll try after work tomorrow.
New plugs fitted but you never know .
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline AshimotoK0

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Re: CB175 running problem
« Reply #4 on: May 21, 2019, 10:12:31 PM »
Silly question but did you check out all of the jets were clear and that they are correct size for your model Rich/ float height is correct Even though carbs are NOS still worth checking.
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline RGP750

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Re: CB175 running problem
« Reply #5 on: May 22, 2019, 08:15:49 AM »
Hi Ash
Yes in fact one of the pilot jets was blocked.
THe only other thing i can't find an answer for is which groove the needle should be in ,
looks to be on the bottom groove, normally the middle i thought????
That will make it richer so why die when choke off ??
Cheers
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline AshimotoK0

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Re: CB175 running problem
« Reply #6 on: May 22, 2019, 08:29:30 AM »
Hi Ash
Yes in fact one of the pilot jets was blocked.
THe only other thing i can't find an answer for is which groove the needle should be in ,
looks to be on the bottom groove, normally the middle i thought????
That will make it richer so why die when choke off ??
Cheers

Did you look in here Rich for groove position? (suspect you already have a paper copy though)

https://www.dropbox.com/s/7bt8uqe4m9mjzi7/125-CB175-CL125-CL175%20Shop%20Manual-1971.pdf?dl=0
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: CB175 running problem
« Reply #7 on: May 22, 2019, 08:36:17 AM »
Hi Ash
Yes in fact one of the pilot jets was blocked.
THe only other thing i can't find an answer for is which groove the needle should be in ,
looks to be on the bottom groove, normally the middle i thought????
That will make it richer so why die when choke off ??
Cheers

Did you look in here Rich for groove position? (suspect you already have a paper copy though)

https://www.dropbox.com/s/7bt8uqe4m9mjzi7/125-CB175-CL125-CL175%20Shop%20Manual-1971.pdf?dl=0

Another thought .. probably a long shot   ::) but they are CB and not CL NOS carbs Rich? as CB's are PW20's and I think CL's are PW22's

Also discussion here:-

https://www.hondatwins.net/forums/41-fuel-supply-carburation/51425-more-carb-tuning-questions-1972-cb175.html
« Last Edit: May 22, 2019, 08:41:18 AM by AshimotoK0 »
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.