CB 125s: Engine Rebuild Pics and Questions!

[speeder#1]

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.

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.

Then came off the cylinder

Combustion chamber is coated in carbon.

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.

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.

Also:
Are there bolt kits for this engine?

 

[crazypj]

Yep, seal just pushes in.
It should be a tight fit, de-burr edge of hole before fitting

 

[speeder#1]

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.

Bonus pic of my 79 kz400 ltd. Im moving so shes going to a new home.

 

[NvgtrWiggles]

Bike Bandit is a pretty good site for getting parts.

 

[crazypj]

You could also try Honda, pretty sure motor is still in production for some market?

 

[speeder#1]

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

 

[briandk]

Never too late to finish it

How is the rest of the bike, lots of work needed?

 

[pidjones]

Even fifteen minutes of work every day will result in a finished product. Just keep at it.

 

[speeder#1]

Never too late to finish it

How is the rest of the bike, lots of work needed?

Everything has to be rebuilt.

 

[speeder#1]

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.

 

[pidjones]

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

 

[Maritime]

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]

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]

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

 

[Maritime]

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.

Re-jetting the stock carb is probably the best and cheapest idea.

 

[pidjones]

Sprocket (s), chain. Such is the way of bikes. They demand more and more (and we lovingly give).

 

[speeder#1]

Sprocket (s), chain. Such is the way of bikes. They demand more and more (and we lovingly give).

So far it’s been fun. The lack of urgency to complete this bike is allowing me to enjoy the process.

 

[Maritime]

always more fun to do a project without a hard deadline for sure.

 

[HerrDeacon]

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

 

[speeder#1]

I will say next time I build a bike I will be buying every part I need ahead of time.