DO THE TON

Blood Sweat Tears and Grease => Projects => Cafe Racers => Topic started by: vwrabbit on May 04, 2017, 21:54:20

Title: 1975 Honda CB125S
Post by: vwrabbit on May 04, 2017, 21:54:20
I've taken over ownership of my brother's old CB125. It's a '75 and when my brother got it back in the 90s, it was near mint. It's survived some stints off-road and at college while in his care.

Now that I have a garage and a little $, it's time to do what I've been wanting to ever since he got it. The plan is to build a cafe seat, clubman bars, convert all lights to LED and 12v. Replace the lollipop turn signals with something a little more modern, and maybe some rear sets.

Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 04, 2017, 21:59:43
Today I replaced the battery with a WPS 12v li-ion battery, a 12v regulator/rectifier and bodged an LED neutral light to verify the conversion worked. I also removed the battery tray, air box and toolbox.

Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 04, 2017, 22:04:47
Now I need to get the stock carb with new float back on. Can't get the bike with a Chinese carb to start. The original float was full of holes. Might also need to clean the points and check the valves. The bike ran two years ago and only had about 2700 miles on it.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 04, 2017, 22:09:52
Once it's running, I plan to strip it down, clean it up maybe a repaint. If I can find a Benelli Mojave or CB160 tank cheap enough, I'll swap tanks.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 09, 2017, 10:50:29
I replaced the Chinese carb with the stock and new float, added some more fuel and it starts but won't run for very long.  Need to double check timing.  It might be due to the fact the stock airbox has been removed...  Carb and jets were cleaned before reassembly.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 09, 2017, 10:52:03
Also look to be missing the "caliper joint - 45104-107-720".  This mounts to the top of the caliper where the fender is bolted on, but my brother removed the fender a while back.  I have the fender, but don't seem to have the caliper joint.  Does anyone have one or know where I might find one?
Title: Re: 1975 Honda CB125S
Post by: crazypj on May 09, 2017, 12:48:02
The cable operated brake can be made to work OK but parts are very rare. The top bracket should be relatively easy to find (eBay, etc) as the nylon and spring steel ratchet assembly is usually trash by now (I saw several 3~4 yr old ones rotted out when I worked at Honda dealers) Automatic adjustment rarely works properly, I found it easier to adjust when dismantled (but PITA as you have to assemble to check clearance)
Larger model hydraulic part is too big so if you find one get seller to take a pic with rule across mounting holes.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 16, 2017, 10:45:19
If I can't find the caliper joint, I'll probably fab something up.  Shouldn't be difficult. 

On another note, I got it purring like a kitten.  Cleaned the carb bowl and the pilot jet.  I also think getting it converted from 6V to 12V helps it run stronger. 
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 18, 2017, 11:05:39
Trimmed up the front fender and mounted it. Need to trim the back more to round it off...

Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 18, 2017, 23:07:13
Finally got my order from SuperBriteLEDs and replaced all of the bulbs. Also replaced the flasher with an adjustable LED compatible one. Turn signals work well. Even the 6v headlight seems to work well with the 12v conversion.

Got a superbike bar from Dennis Kirk that I need to drill out for wires. I'm going to mount it upside down to see if that works well. Won't be as aggressive as a clubman bar.
Title: Re: 1975 Honda CB125S
Post by: hillsy on May 19, 2017, 04:18:40
Just cut some slots in the bottom of the switch blocks and run the wires underneath the bars. Seriously, drilling the bars and feeding wires through them is a pain in the ass - especially when you want to change them again.....which you probably will.......
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 19, 2017, 08:07:52
Thanks for the tip! Wasn't looking forward to drilling especially if I switch again.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 20, 2017, 00:49:01
Got the superbike bars mounted upsidedown. Looks pretty good. The wife isn't so keen. She says it looks like a crotch rocket now. Thanks to hillsy's tip, I notched the controls to avoid drilling. Need to notch the right side a little more though.

I need to get better pictures tomorrow.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 20, 2017, 17:48:58
Got it cleaned up a little with some help from the youngest. Hopefully she'll appreciate this enough to want it someday.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 20, 2017, 17:51:18
I also noticed that the steering stop is either broken or purposefully allows more turn to the right. The horn button will hit the tank when parked on the kick stand.
Title: Re: 1975 Honda CB125S
Post by: vwrabbit on May 20, 2017, 20:33:29
Cleaned the chain and ran it on the center stand. Boy that back wheel needs some truing!