CB 125s: Engine Rebuild Pics and Questions!

speeder#1

New Member
I picked up a Honda CB125s a little over a year ago. Its been sitting under the porch in a tarp for awhile so i figured it was time to dive into the motor and get this thing together. The motor had a good amount of dirt and some oxidation. Cell phone pics cause i dont work on my bike in a photo studio.
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Took the head off to see how the insides are. Piston has a good amount of carbon build up on top but no visible damage.
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Then came off the cylinder
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Combustion chamber is coated in carbon.
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I cleaned it up some today. used brass brushes to clean out the fins and get all the oxidation/dirt off the head. Head still needs some porting/polishing work.
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I do have one question. I have yet to get a manual to know the answer so i was wondering if someone could tell me if i can replace this seal without splitting the case? I think it leaks oil here.

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Also:
Are there bolt kits for this engine?
 

crazypj

Split personality, I fake being smart
Yep, seal just pushes in.
It should be a tight fit, de-burr edge of hole before fitting
 

speeder#1

New Member
Another question- Where do you guys suggest I get parts from online, outside of ebay?
Clean and painted atleast. Need to get a gasket kit, valve seals, and piston rings.
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Bonus pic of my 79 kz400 ltd. Im moving so shes going to a new home.
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crazypj

Split personality, I fake being smart
You could also try Honda, pretty sure motor is still in production for some market?
 

speeder#1

New Member
So blast from the past. Started working on this thing again. Not having a bike for 8 years has inspired me to get this thing running. Cleaned the head up and ported polished the exhaust/ intake. Cleaned the valves up and lapped them. “Decked the head with some wet sand paper and a granite counter top. Waiting on an eBay rebuild kit to come and and I’ll move forward. Super low buck
 

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pidjones

Over 1,000 Posts
Even fifteen minutes of work every day will result in a finished product. Just keep at it.
 

speeder#1

New Member
eBay Cylinder and piston kit came in. Cleaned up the carb and some other small parts. Still not sure if I should rebuild this carb or go with a new larger one.
 

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pidjones

Over 1,000 Posts
Why do you think it needs a larger carb? I'd start with stock until it is sorted and demands more.
 

Maritime

Over 10,000 Posts
Since my 125 can run rich at the slightest miss adjustment I think the stock Carb will be all you need unless you are pulling air box etc.
 

speeder#1

New Member
Why do you think it needs a larger carb? I'd start with stock until it is sorted and demands more.
Im not running the air box, I’ve ported polished my head some. Just an idea, it’s cheaper to rebuild the stock carb so I’m probably going that route.
 

speeder#1

New Member
At the point where I gotta buy more parts to move forward.
 

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HerrDeacon

Over 1,000 Posts
Don't enjoy it too much or your project will end up like mine :p Just kidding of course, its great to be able to take your time with it, I hate rushing through things.
 

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