Author Topic: 1975 CB125S Bogging Under Load  (Read 479 times)

Offline albent_33

  • Posts: 2
1975 CB125S Bogging Under Load
« on: May 23, 2017, 10:27:24 »
Hi all,
I am new here and I have started my first motorcycle build. It is a 1975 CB125S that sat in a basement for 15+ years untouched. I picked it up a few weeks back for free and cleaned the carb but found that it was a hopeless cause due to the 15+ year old gas grime on the inside of everything. I ordered a new carb from Wincycle in Miami (link below) and a new fuel petcock from ebay (link below). I also cleaned the tank with vinegar and a power washer. The inside of the tank is all clean and fine. I filled the fuel bowl on the carb with some gas and fired the bike up after changing the oil. I ran fine but I couldn't rev the engine because I cut the throttle cable when taking the old carb off so I order a new one. Then yesterday, I received m package with fuel lines, an inline fuel filter, and my throttle cable. I put it all together and it started right up and idled fine and then I went for a ride but I would put it into 1st and it would run fine. the I would try to ride it but it needed about 5k rpms to keep it from stalling when starting off. Then when trying to accelerate, it bogs down and I have to pull the clutch in to keep it from dying even going down smallish hills. Please help me out! Thank you!



I ride dirt bikes so I know how to work the clutch and throttle.

Offline datadavid

  • Posts: 1363
Re: 1975 CB125S Bogging Under Load
« Reply #1 on: May 25, 2017, 03:48:43 »
How much do you weigh? 😃

Offline albent_33

  • Posts: 2
Re: 1975 CB125S Bogging Under Load
« Reply #3 on: May 26, 2017, 09:02:54 »
I weigh about 125 and I'm 15. I am also using the stock airborne but I am not sure if it is the stock filter.

Offline SONIC.

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  • Posts: 6057
  • Reminds me No, I'm sure of it. I hate him
Re: 1975 CB125S Bogging Under Load
« Reply #4 on: May 26, 2017, 09:45:09 »
Congrats on the first bike!
Grab a maintenance manual and go step by step through the tune up procedure and then report back.