1974 CB125S rebuild with no experience.

LittlePece

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Joined
May 9, 2026
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Location
Pacific Palisades, CA
Hello Vintage Honda Twins!

Thanks for the warm welcome. My name is Jack.

I've been doing lots of research on my own. Watching 2vintage on Youtube is especially helpful because of all the similar and identical Honda's he works on.
I guess my concern is when it comes to buying parts. For example, I'm missing the whole front brake system. I've been looking on David Silver Spares but with no experience I'm not positive about every single part I need to buy. I could just go down the list and buy everything labeled "front brake" on DSS but I'd prefer gaining some confidence in my purchases through you guys.

Here's the beast.

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I should clarify what I'm going for. I want to keep the original design but I'm not concerned about parts being original. Seeing as how I don't have the side panels and I need to replace the tank I'm still deciding between restoring the blue or going for the orange. I love both.

The seat
Let's get the easy out of the way, it needs a new seat. I see lots of aftermarket seats on Ebay, usually coming from Thailand. Does anyone know how the quality of these are or have other suggestions?

The tank
As I mentioned above, the tank is in really rough condition. Without having much knowledge about this, I'd say it isn't salvageable. I've read if you fill it with vinegar and let it sit for a week, then throw some bolts in it and shake it, it'll clean it up. I'll try this out just to see how far it gets but it seems pretty rough to me.
I found this guy Raretro Moto who sells these tanks ready for paint. Then I'd just need to find somebody to paint it like the original. And I need to find the Honda logos to go on the side.
I also need a petcock.

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Inside of tank

The front

There's a fair amount of "cosmetic" things that are needed and easy to replace like most of the light covers.

The most glaring concern with the front half of the bike, as mentioned previously, is it's missing the front brake. I could really use some help here to determine what parts I need to buy to get this put back together and safe.

The brake lever/handle is missing. There's a cable still connected that is hanging down by the wheel. It looks like every other component is missing. What does my shopping list look like for this?

Also, I love this front tire. What tires should I look into getting? What size and brand and all that?

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Continuing on the handles, the throttle is stuck. The butterfly valve in the carburetor is stuck down because of this. The choke on the carburetor works great though.

There's also a cable from the bottom of the speedometer that is hanging by the wheel. Should this need replacing?

The clutch lever/handle is snapped in half. The clutch cable works, it moves the piece connected to the transmission, but it's super stiff and needs two hands to move. Does this just need lubrication inside of the cable?

Lastly on the front, is it normal for this whole front section to move like this lol? What am I missing here that will keep all of this stuff in place?
Moving front

Coming to the middle of the bike

I was told when I bought the bike that the engine has good compression. Kick starting It feels and sounds like that to me I don't know what I'm talking about. There's this great 2vintage video which I'll follow to learn how to clean the carb and set up the engine.

I can tell that I'm missing a battery, an air filter and an air filter to carburetor tube. Then, of course, the side panels.

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Coming to the rear of the bike

The rear brake pedal is connected to the rear brake rod and functions but the other end of the rod is disconnected from the brake and all bent out of shape. Brake rod I'm not sure how to determine the status of the rear brake itself.

I'm also missing my chain.

There's a fair amount of rust on the inside of the rear fender. Should I do anything about this and if so, what? Speaking of, the battery and air filter housing is super rusty. Is this worth being replaced or fine as is?

Lastly, the wiring seems to be a total mess. There's loose ends all over the place. I have the wiring schematic for the bike, so I'll have to go through and trace every wire and replace and reconnect where necessary. I'm not too worried about this part but I know it'll be tedious.

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Lastly, any tips on how to do a general cleaning would be much appreciated. Can I just blast it with carb cleaner? Tips for rust removal and rust prevention would be appreciated as well.


Well, I think that's about it. If there's anything I've left out, please point it out.

Again, thanks in advance for any help. I'll be very grateful for whatever I can get to start me moving in the right direction. I'm hoping to get this in decent shape by the end of June.

Let me know your thoughts!

Thanks,
Jack
 
Last edited by a moderator:
partzilla will have some oem parts and so will 4in1....
oh forget vinegar/nuts in tank instead use rust 911. not toxic not harmful dont know if that tank is salvageable... rust 911 will clean your airbox too oh your 74 is a 75 model good luck on finding brake components
 
Gibbs and brass wool for small area rust removal and prevention bikes looks so good to have that bad of a seat and tank.... Gibbs is available from amazon can also be ordered from wal mrt
 
i would suggest partzilla first for needed oem parts....silver spares is considerably higher..... no parts for frt brake are showing available, maybe cmsnl netherlands? OR ebay for tank, seat and brake assy parts...good luck if i can assist..pm
 
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