CB125S "Susie" Take Two

http://www.bike-revival.co.uk/trail.html
Top ones ..... had them on same frame as yours.
Nice damping and lifts the back end an inch, combined with an inch drop upfront really livens up the handling. The TL 400mm shocks are too long for the frame.
I'm 10 1/2 stone ... errr ..thats about 150lbs to you, these worked well for me, because they did control the rear end as opposed to the regular pogo sticks. Hagons are nice but without a much stiffer frame to gain the benefits, its not a cost effective expense. An ace tank and seat would be a better use of the saved cash because it would look much faster standing still. You know it makes sense.
 
http://www.ebay.co.uk/itm/Carburetor-Honda-CB125S-XR100-XR100R-CRF100F-XL100S-XR200-XR200R-Carb-/221382441173?hash=item338b6bf8d5
Cheap as chips. its a good carb for the engine. If a bigger one would have given more gains honda would not have fitted it to the XR200!
The 100 ehaust will be fine so long as you give some back pressure after the header. Any bigger diameter will not scavange the gasses properly and give you lots of noise but a performance loss.
Smoothing the ports and grinding out any casting burrs does make a difference but relap your valve seats to get a good seal otjerwise the extra flow will be worthless.
 
Re: CB125S "Susie" Take Two

Thanks for the replies. Valves are new and seats have been relapped already.
 
Two months later... Basically my internship has been taking up a lot of time, and visiting with old friends before they left took priority over working on the bike. However, most are gone now so my weekends can go to the bike.. Today my buddy and I got some work done.
New brake pedal installed
Seat pan started. Bent it up on a table and cuts were made with an angle grinder and smoothed with a flapper wheel. Not sure if the pan will be hard mounted to the cowl, or sit inside of it. Currently the back fits inside it, so I could do either way. The fender that's in the picture won't be on there. It's just there for me to check tire clearance to the seat pan. Pic from the side:
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Worked on the speedometer/headlight mount. Chopped and smoothed the idiot light and original speedometer mounts. Pic:
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Erskine, those shocks look good. Any idea if there's a distributor in the states?
On the carb... Main jet holder's threads are a bit messed up. Not sure if I'll be able to get jets in there, and I can't find a new one for the vm20. In that case I'll get the new carb and go from there.
To finish it up, an obligatory "beer and welding" picture.
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I sent them an email, and they can't ship to the US. Oh well. I'll keep looking for a decent set of SL125 shocks.
I've been looking in to the 12V Conversion, what's the word on coils? I've seen wiring in a 2 Ohm resistor with the stock coil, but mine is beat up so I was thinking about switching to a 12V coil. I already have the 350 stator.
 
Re: CB125S "Susie" Take Two

After two and a half years I finally found a rear tank mount!! For some reason there are none of these style (78-80) for sale. I just happened to hop on eBay and find one!
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Mega thread revival here...

Got Susie back to my parent’s house so I can try to get this project rolling again. Bought a new carb (VM22 copy) and threw it on. After a couple hours of trying to get her started and a bruised calf I’m stuck scratching my head.
Spark is good, timing is set so that the points open at the “F” mark, compression feels good, and the plug is wet with fuel if I pull it after kicking for a while.
Even tried bump starting but the most I could get was a little chug that I couldn’t rev out and it would die as soon as I put the clutch in.

Any thoughts on why I can’t get her started?
 
I scrolled through pretty quickly. Test compression? Leakdown test?
Easy enough to pull the carb and exhaust off of this bike to do them properly.
 
This is gonna sound off some.

I have a CB100, and it won't run unless the tank is full.

My tank is fairly clean, new petcock, one of those carbs you have, new fuel hose, everything new including points and plug.

Nothing, then one day just for some reason, filled the tank all the way instead of just enough to get it running I thought.

She runs really well, in the back yard, don't have tags or insurance to be able to get it out on the road to stretch it out.

But......it would not start and run, until I did that.

Just saying...............................
 
Also, I'm in the market for a 12 volt conversion too.

Really like to get the 6 volt working right first.
 
Hm, interesting. Right now my gas tank is just a water bottle zip tied to the frame, since the tank got a bit rusty after sitting for 6 years.
I’ve got the parts for a 12V conversion but also want to just get it running on 6V to start.


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Been there, what appears to be enough fuel can be barely enough to get enough flow to start, once running
Hm, interesting. Right now my gas tank is just a water bottle zip tied to the frame, since the tank got a bit rusty after sitting for 6 years.
I’ve got the parts for a 12V conversion but also want to just get it running on 6V to start.


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Hang the bottle a few feet above the carb so gravity will let the fuel flow.
 
Well, last night I tried starting it with my dad holding the gas bottle up in the air. After 15 minutes or so, I was actually able to get it running for ~30 seconds. Even almost revved out too. Funny thing is though, after that I couldn’t get it to start again. So, since the gas bottle was running low I decided to fill up another one and try again today. No luck, and can’t figure out why. I was able to get it to pop a few times, but nothing more.
Not sure why, but my trip home is over so Susie is gonna sit until Memorial Day weekend at the earliest, at which time I’m thinking about getting the tank cleaned and brimming it to see if that does the trick. Otherwise might just splurge and buy a legit Mikuni instead of the knock-off I got.


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Hang in there, you'll get it.

Too bad you have to wait so long, will be waiting to see how it turns out.

I'm actually going back to the original carb, just rebuilt it, so will be putting it on soon.

Good Luck.
 
Well, Memorial Day didn’t happen due to COVID, but I did get a week off so I’m back home and trying to get some work done. I bought another carb, seems like a much better VM22 copy so we will see. I did notice the float was bent on the old one, maybe that was the problem.
Today I got the new seat mounted, I liked the eBay seat on the Twinstar so I decided to buy another one for the 125, and I’m pretty happy with it.
Now that the seat mount is done, the tank is soaking with some CLR and water to get prepped for RedKote. Once that’s done I’ll brim it with gas and try to get it started using the new carb. In the meantime here’s the latest pic!
 

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My little CB100 still would not run right, even after the full tank.

So, bought this and now it fires first kick, even after sitting a week or two.

Can even run it till gas gets low.
 

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Well, the CLR did a good job of cleaning the tank out, however I managed to totally botch the red kote. Spilled everywhere and of course we didn’t have any acetone or MEK in the garage so I wasn’t able to clean it up. In a panicked attempt to salvage my paint I sprayed it with goo gone, and I’m concerned some got in the tank and messed with the liner. It’ll have a long time to cure (5 months?) so if the inside looks fine I’ll just sand it back and respray. Otherwise I might roll the dice and buy one of those universal tanks off eBay.
It was a learning experience for sure, I probably would’ve been better off just brimming the tank with fuel and adding a stabilizer once it was cleaned out. I can also say I’m never going to attempt lining a tank again.
Here’s how she’s sitting now, tucked away until Christmas.
 

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My little CB100 still would not run right, even after the full tank.

So, bought this and now it fires first kick, even after sitting a week or two.

Can even run it till gas gets low.

I bought one of these back when I was doing the wiring on it in 2013. I’m also planning on converting everything to 12V around Christmas, time permitting.
 
I bought one of these back when I was doing the wiring on it in 2013. I’m also planning on converting everything to 12V around Christmas, time permitting.

Cool, I'll be waiting, will do the same.
 
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