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mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/23/20 6:39 p.m.

A new project came home in the truck last night. 

It's a 1975 Honda CB125S and it ticks a few boxes that I've been meaning to tick for a while. Firstly the bike and I are the same age. Second, if it all goes well I'll be building something properly beautiful. My intention has always been to build one beautiful thing while I'm able and this has that potential. Not a car like I always thought, but something I can be proud of. Next, it will be a race bike. Always wanted to build a race car. The scale here is different, but the intention is the same. Lastly, it's a proper barn find. It's a one owner bike that has been in a shed since 1981. It even comes with the title and original owners manual. 

Ransom
Ransom UltimaDork
2/23/20 6:44 p.m.

Awesome!

My first (and so far only) motorcycle racing was on a CB160, which developed sort of a cult following (and sort of still does), running a sort of "gentleperson's agreement" subclass within 250 Vintage. There have been some beautiful bikes built.

I look forward very much to seeing what you build!

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/23/20 6:46 p.m.

Deucekid#3 is excited about the bike too. She found the proper race position and says the size of the bike is about perfect. 

She and I spent some time looking at the bike, checking out the tool kit, that sort of thing. 

The bike kicked over, shifted gears and had good looking non contaminated oil. 

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/23/20 6:52 p.m.

Here I made a decision to do a nice slow Mazeduece style thread where I poke around and explore while I learn and fix. It was going to be awesome. Unfortunately (for this thread) my racing/minimoto partner came over and grabbed the tools.

Things quickly devolved. We spent a few minutes figuring out how to bypass the key. Tracing more wires led us to the junction of all things electrical on the bike. This is all untouched factory wiring. Honda did things differently back then. 

A multimeter and scant knowledge of what colors Honda deems important got us working around off switches and and other electron diversions and we ended up getting sparks at the points. Neither of us know anything about points. That was fun. Carb came off, starting fluid liberally applied and we got exactly two revolutions to fire before a high five victory dance.

39 years in a shed and we have combustion on the first day at the cost of a nice proper build thread start. Parts are on their way, very busy week, lots of reading to do about ignition theory. 

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/23/20 7:06 p.m.

In reply to Ransom :

Luckily there are a TON of parts available for these bikes and a very active scene both in the US and worldwide in racing and restoring them. My build will be headed in the clip ons and full fairing direction but the bike really is pretty how it sits. Even though we got combustion, the bike is rough enough that I don't feel bad about cutting it up if the end result is to save it. I may ask you a bit about the actual act of vintage racing as things progress. 

Pete Gossett
Pete Gossett MegaDork
2/23/20 8:49 p.m.

In reply to mazdeuce - Seth :

Let me know when you're ready for a CB350, my FIL has had one sitting in his garage for decades. 

Woody
Woody MegaDork
2/24/20 8:39 a.m.

This is awesome. I love old Hondas, especially small ones.

My first suggestion would be to clean every single ground and bullet connection. That will make everything easier. Hondas of this era like to melt out the back of the tiny fuse box, and clean connections will go a long way toward preventing that.

And if you really want to have some fun, avoid the big Chilton/Clymer manuals and see just how much you can accomplish with the factory tool kit and the owner's manual. Honda really got that kind of stuff right back then.

Enjoy!

 

Woody
Woody MegaDork
2/24/20 8:52 a.m.

Is this the look you're going after?

 

This is my old 1977 CB400F Super Sport. I rode it for a few years and then gave it to a friend back when I had too many other bikes. These photos are from the last time that I saw it, but I think it's probably sitting in the same spot, still covered in the same kydex dust.

Old Hondas are fun.

Woody
Woody MegaDork
2/24/20 8:56 a.m.

The '75-'76 CB400F had those little factory rearsets that I added to my '77, which might also work for your 125S if you can find them.

Woody
Woody MegaDork
2/24/20 8:58 a.m.
Pete Gossett said:

In reply to mazdeuce - Seth :

Let me know when you're ready for a CB350, my FIL has had one sitting in his garage for decades. 

CB350K or CB350 Four?

Pete Gossett
Pete Gossett MegaDork
2/24/20 9:31 a.m.

In reply to Woody :

I'm pretty sure it's a 73, like this, in the same color blue as the 2nd pic. I remember it's missing one side cover & hasn't been started in decades. 

ebelements
ebelements Reader
2/24/20 9:41 a.m.

Nice score!  If you haven't ordered it already, grab the Vintage Connections CK-1. SUPER HELPFUL on these old bikes, especially if you want to keep things stock looking. When I "british-ized" my '74 CB450 it was a godsend.

http://www.vintageconnections.com/Products/Kits

 


fatallightning
fatallightning Reader
2/24/20 12:54 p.m.

I've found these guys extremely helpful https://www.common-motor.com/ They're more about the twins like 350/360 and 450/500, but I'm sure a lot applies. They have a good video about doing the points timing and valve adjustment.

NBraun
NBraun Reader
2/24/20 1:55 p.m.

A friend of mine had one of these and he was able to put together a 175cc franken motor using parts from honda 3 wheelers. Not exactly sure what all he did, but it may be something to look into.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/24/20 5:22 p.m.

In reply to Woody :

Going more for the mid/late 70's factory endurance racer look. 

Woody
Woody MegaDork
2/24/20 5:36 p.m.

In reply to mazdeuce - Seth :

Yes. That is preferable.

 

AngryCorvair
AngryCorvair MegaDork
2/24/20 8:30 p.m.

In reply to Pete Gossett :

IDK about mazdeuce, but I'm ready for a CB350!

Pete Gossett
Pete Gossett MegaDork
2/24/20 10:52 p.m.

In reply to AngryCorvair :

It's not all that far from you. He's about 2-hours south of Chicago. 

Ransom
Ransom UltimaDork
2/25/20 12:59 a.m.
mazdeuce - Seth said:

In reply to Woody :

Going more for the mid/late 70's factory endurance racer look. 

You may wish to visit Glass From The Past...

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/25/20 7:06 a.m.

I'm reading everything and clicking on all the links and going down every rabbit hole suggested even if I'm not replying to your comment. Huge appreciation. Super busy with track meets and work and getting the race bikes ready for this next weekend. I'll fill in the thread more when I get breathing room. 

In the mean time I'm playing with things about 10 minutes at a time. To Woody, this is the fuse box. One glass fuse. About as simple as you can get. 

The main power distribution seems to be through the run switch on the right handlebar. It's like a mini bus bar that sends power where it needs to go. 

Simple. It also gives me some good insight into wiring my XR100 for street use. 

nocones
nocones UltraDork
2/25/20 9:04 a.m.
Pete Gossett said:

In reply to AngryCorvair :

It's not all that far from you. He's about 2-hours south of Chicago. 

I'm about 2 hrs south of Chicago..  ..

Pete Gossett
Pete Gossett MegaDork
2/25/20 9:38 a.m.

In reply to nocones :

He's in Rossville, lmk if you're interested and I can get more details. 

AngryCorvair
AngryCorvair MegaDork
2/25/20 12:51 p.m.

Get it, nocones! I'm in no position to drag home another project.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
2/25/20 3:51 p.m.
nocones said:
Pete Gossett said:

In reply to AngryCorvair :

It's not all that far from you. He's about 2-hours south of Chicago. 

I'm about 2 hrs south of Chicago..  ..

If you don't get it.....I have to bring two sets of wheels north in two months which means I have to drive the truck which means......motorcycle?

EvanB
EvanB MegaDork
2/25/20 4:26 p.m.
Pete Gossett said:

In reply to nocones :

He's in Rossville, lmk if you're interested and I can get more details. 

Hmm, that's under 5 hours from me. 

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