Honda Twins banner
1 - 12 of 12 Posts

·
Registered
Joined
·
439 Posts
Discussion Starter · #1 ·
trolling for feedback on my CB125s carb problem. the original carb body deforms when tightened to the cylinder. this in return, siezes the throttle slide. I've flatened the mounting surface several tines, tried a variety of o-ring and gasket materials, and it continues to happen.

so, the question: will a cb175 carb work well on my cb125? i dont have the carb or engine in front of me, but can check suggestions over the weekend. TIA people, danWI
 

·
Sensei
Joined
·
27,182 Posts
The 175 carb is much smaller...... 20mm (CB) or 22mm (CL) vs the 125's 24mm... That two mm represents about a 18% increase in flow volume.....would run, but how well?
 

·
Registered
Joined
·
6,495 Posts
danWI said:
trolling for feedback on my CB125s carb problem. the original carb body deforms when tightened to the cylinder. this in return, siezes the throttle slide. ]

Dan -

I can't imagine why that would happen.
It's pretty much built like a regular ol' 175/200 carb, don't think I've ever heard of it before.
The only thing different about the 125 setup is the two insulator/3 gasket/o-ring manifold setup.
The thicker insulator is NLA, but the other stuff is still at Honda.

I always have to be real careful installing those carb types - tighten one side a little, then the other, etc. The o-ring tends to get squished out of its groove.

I think I have a bunch of jets around your size (98/38, right??)
 

·
Sensei
Joined
·
27,182 Posts
I've seen the flanges deform on carbs from overtightening, but hard to believe that that force would transfer to the slide chamber area..... Could you cut/file off the flange and rubber mount it like the XR-75?
 

·
Registered
Joined
·
439 Posts
Discussion Starter · #5 ·
well alrighty then, lets take a step back.... when the carb is mounted lightly-snug to the carb studs, the slide moves. When the nuts are tightened to spec, the slide freezes. any ideas? otherwise, it sounds like the cb175 carbs won't work. I'll FS them in a separate post later this week.
 

·
Registered
Joined
·
439 Posts
Discussion Starter · #6 ·
<nudge>
 

·
Sensei
Joined
·
27,182 Posts
I think I'd try a thick cork gasket... If it doesn't work, you're not out much...if it does.... :D :D :D :D :D :D :D :D
 

·
Registered
Joined
·
439 Posts
Discussion Starter · #8 ·
I tried this with both cork and rubber gasket material the same OD and ID of carb runner. Didn't prevent the binding problem. I do wonder if it has something to do with the runner-cylinder contact area.... i'm guessing now. danWI
 

·
Sensei
Joined
·
27,182 Posts
I'm back to a new flange with a section of hose and clamps.............
 

·
Registered
Joined
·
439 Posts
Discussion Starter · #10 ·
Steve: stopped over in storage and looked again at lil honda. she'sa 1974 cb125S with one-piece head. joined the Honda Single group (now i just need to join the triple, 4 and 6 cylinder groups for a full house!) and searching out a replacement carb and runner. if this doesnt solve issue, then rubber mount may be the route for the time-being. thanks for the assist, danWI
 

·
Premium Member
Joined
·
771 Posts
Hey, Dan,

What group is that? I have several Honda singles (100 & 125s from early 70s) and I'm always looking to get more info!

Thanks,

Kirk
 
1 - 12 of 12 Posts
Top