CB125K3 - Future Project

[Toko_Jo]

What docs. do you have with it if any? Bit of a problem if you have nothing and it's an import.

[Craizeehair]

Currently working on that with the PO

[Craizeehair]

I found myself with some time to kill this weekend and as the CB350 frame is still away waiting to get some welding done, I decided to see what was what with this little CB125.

I sorted through the assorted tubs and boxes of bits and managed to gather up all the carb parts and reassembled them and fit to the bike. The throttle cable hadn’t been fitted properly and wouldn’t move so that came apart and put back correctly. Popped a battery on, checked compression, checked for spark, all good there, which surprised me. Hooked up the remote fuel tank and connected to the carbs, a quick tap on the bowls stopped the right hand side overflowing.

I’m not sure if it it’s necessary but there is no electric start on this, so I gave it a few prime kicks before turning the key on and I kid you not, it coughed on the first kick and fired into life on the second, the old gentleman I bought it from said it had been sitting for many years as it was one of his late fathers projects that had never been got round to, so I really wasn’t expecting it to spring into life quite so easily, I was massively surprised and impressed.

I do have a couple of questions though if anyone could help?

The exhausts seem to be one piece, there are no clamps joining the silencers to the down pipes, the left hand one is solid and one piece, the right hand one, separates and pulls apart and is leaking at that join (circled in red below)when running, is there a way to join / reseal this connection?


Also, the coil is producing spark at both plugs but the right hand lead does have play in and out of the coil if pulled , I was convinced it wouldn’t work as there is so much free play in and out of the coil… for want of a better phrase. I was thinking I could maybe epoxy around the lead where it enters the coil to stop the movement and preventing any issues down the line, I’m not sure if that makes sense reading it back but I don’t know how else to explain it!

I have a feeling that if I decide to keep it and finish the job, finding all the bits I might need could be a bit of a job.

[TrickyMicky]

Have just zoomed in on photo, KMH speedo and a yellow headlamp bulb definitely point to French origin. Have fun.

[Craizeehair]

Thanks.

Yep definitely French, the VIN plate on the rear of the frame is in French, I didn’t notice that when I first got the bike.

[TrickyMicky]

Looking ahead, (a few weeks???) to when you are ready to kick it into life, do not be tempted to re-position the kick start into a more vertical position. If they are in any way similar to the old CD175, people used to do this, and on a good full swing right to the bottom the mechanism used to punch a hole in thetop casing.

[Craizeehair]

Ah ok, that’s interesting as I had previously looked at a CD175 tha had a crack in the top casing that I couldn’t work out, that now makes sense.

[Johnwebley]

An early forerunner of the 175 and 200,

If you decide to get a new coil, ensure it has a low ohm primary circuit,
I think close to 3,

I had a coil with a higher resistance, and it wouldn't spark above 7k

Took me ages to find out the issue

Sent from my SM-A546E using Tapatalk

[AshimotoK0]

You need to speak with Richard on here member RGP750 .. he has almost finished restoring a rare UK one ...  very few genuine UK CB125K3's sold in the UK....  Not sure why as brilliant little bikes.

https://www.sohc.co.uk/index.php?action=profile;u=13200

[Craizeehair]

Well, I have been tinkering away with this little thing and I’ve managed to get it reassembled, I’ve had it running and riding up the road, it goes through all the gears and stops!

I did have a bit of a job getting the paperwork sorted but nothing majorly difficult, just time consuming, so it now has a V5 in my name.

I’ve not 100% decided what I’m going to do with this one yet but I’m pretty sure I will sell it as a runner with paperwork. I will hopefully be getting the frame back for the CB350 K2 that I bought last summer after its had some welding done and been powder coated, so that will need putting back together and I’m also meant to be picking up an XL350 soon, I just don’t have enough room for everything.

It’s been really interesting working out what was in the various boxes, what was needed, what goes where etc… I even had a go at shortening the brake and clutch cables, which worked a treat.

Thanks as always for the help and guidance here.

[Bryanj]

Just to eventually answer one of your first questions, must have missed this post, the original exhausts were one piece but you could buy at one time pattern silencers that looked the same and slid over the original front pipe.
Curing an exhausr leak at the original joint will probably be difficult, possibly carefully packing with exhaust past may work

[AshimotoK0]

Just to eventually answer one of your first questions, must have missed this post, the original exhausts were one piece but you could buy at one time pattern silencers that looked the same and slid over the original front pipe.
Curing an exhausr leak at the original joint will probably be difficult, possibly carefully packing with exhaust past may work

Pretty sure they were two piece Bryan i.e. not welded together ( like the 1st CB250K0 ones) ... they were held together by a crimped band.

That's a rare bike ... Lord knows why Honda UK only sold a few dozen even though it was in their brochure. 5-speed gears and twin carb head sought after by CB92 owners.

[Craizeehair]

Curing an exhausr leak at the original joint will probably be difficult, possibly carefully packing with exhaust past may work

Thanks Bryan,

I did wonder if something like that may be a possibility, I also came across JB Weld High Heat whilst looking for a solution, I did think that might even be a possibility? I haven’t done anything with it yet, I doubt I’ll get too many chances, so it’s still getting a good thinking about.

I have been trying to get gauge what a fair price might be for it now it’s complete and has a V5 but I can’t find any others for sale!

[Spitfire]

Now that is a nice looking bike, love the style of those era bikes.

Cheers

Dennis

[Laverda Dave]

Good job there 👍.
They are really nice looking bikes considering it's only a 125 with big bike features such as a TLS front brake.
Is that the same bottom end as the 160/175/200?