sebatron's CB125N build - I'm gonna call it "CB229S"

is it ton-capable?


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sorry for the lack of updates/photos guys. they're all on the digital camera with the bike (30mi away)
just a recap of last weekends progress:
-headlight fitted
-rearsets connected and functioning (need to get a tap to shorten the shift rod, it's wayy too long atm)
-made up a brake rod from scratch
-made new exhaust from the one that came with the motor - the original snaked over the clutch cover and ended up pointing directly at the helmet lock/rear shock. new one's underslung.

on that note - is the pipe "long enough"? I'm only going to extend it by about 3" and put an internal baffle in. i wanted to do a tuned length exhaust, but i can't find cam/valve specs for the motor and i don't feel like opening up a new crate motor.
any risk of burning up a valve or anything?
 
Couldn't see how a little shorter would burn a valve (I really hope not cuz mine's shorter too) but you could email Michael Bateman about the exhaust/cam specs. Might take him a little while to respond though.
 
Crap, I can't keep these things together in my head. Bateman races CB/CL 175's and knows them inside and out. Which doesn't help you at all. Sorry again man!
 
sebatron said:
It's all good - I'm still psuedo-embarrassed by the CN motor so I tend to gloss over that :p

I wouldn't be dude. I just picked up a 200cc version for my 100 on craigslist for $100. It's brand new. I'm gonna rock it too...BUT, I am going to "de-cheap" the appearance of all of the chinese logo crap.

An I wouldn't worry about burning a valve as long as you have some backpressure in there, which you are with the baffle.
 
yeah i'm planning on de-cheap and de-new'ing this one once it's running. found replacement covers for ~$30USD a piece in case I sand too far :)
the replacements come in both black and silver, with and without brand markings. easy!
 
just realised that old video didn't work at all. here it is on youtubes:
http://www.youtube.com/watch?v=6zW0lvqt0Ns
(i can't work out how to embed it :()
 
alright, i'm getting ready to start ordering the rest of the parts I need to finish this off.
an issue though: old honda motor used a 22mm carb, with a pretty well straight rubber "manifold".
new motor came with a ~60degree bend, with a 30mm throat. it points right into the frame or out the side.
i'm picking up a 30mm flat slide, so 30mm is the way to go...
i haven't any experiencing welding or brazing aluminium, so i'm hesitant to recycle the new manifold.

i can't find shit. i could make it out of mild steel, but financially theres no point.

has anyone got a source (that'll ship to australia) for a 30mm short and straight manifold, or a rubber flange type manifold like the original had?
 
Hi Sebatron.
Sorry for my English.
I think you are doing a very very nice work.
When i saw your bike, I couldn´t resist "the Photoshop calling".
Cut tank, 70% headlight size, cafe seat, extend and bend rear fender
It is just my idea of a cafe.
I´m really looking forward to seeing your project finished.
Thanks and sorry again.
I don´t know if image is attached
 

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wow - thanks for that! i've done some penscribbling, but that's more or less what i was going to do for the seat anyhow!
i hope to get started on it soon, i've got an "interesting" idea for the seat structure that i'm gonna play close to the chest in case it fails dismally.

i admit i do kinda regret not doing the seat hoop, clearance is a bit of an issue though and as i mentioned initially, the powdercoating was pretty much done in anger after a botched paintjob.
i really (really) wanted to get a tank from roccity for this, and wanted the gp tank. what the photo doesn't show is just how SMALL the bike is, and i wanted to retain 2 seats. this is my first build and i didn't want to overinvest financially in case i gave up.

good work on the photochop :)
 
Alright, it's been a while. I've had to work last few weekends and only managed a few hours on the bike yesterday.
But, i've completely finished both the gear linkage and the rear brake rod I made up.
If you'll recall, my shift rod was way too long. logically i saw it to the appropriate length (removing equally from both sides), leaving a section on each side to wrench.
doh, the rod wasn't tapped terribly far in. :(
i have a decent amount of taps and dies but none for reverse thread. shit.
following a little of how i did my brake rod, got some steel bar, threaded it, and threaded as much in as i could on the two pieces after removing a section from the middle. red loctite, screwed tight, and hope for the best. there's no play in it so i think it'll be fine.
again with the photos - left the camera behind :( only got what i took with my phone.
so that's a victory - good shift action, comfortable angle. win.
the brake rod was finished but i didn't like the look of it. thought about painting it (it's already been cured in engine clear) but ended up heatshrinking as much as i could, leaving the eye and threaded sections bare. feels good. win!

again with the photos :( might be able to make out the finished product in one of the photos at the end of this.

anyway, my missus and i ordered a bumload of parts - almost everything left, except battery, speedo and taillight. i'm still working out the details for the rear so i don't want to commit to one taillight yet.
the only thing that's come in so far is the fenders.
i'm using repurposed CB100 fenders (with a sticker saing S90, strangely). i will use a front fender, mounted to the swingarm for the rear. that part will be pretty easy, so i focused on getting the front done since my time was limited.
problems everywhere! i have a disc front end, so the front fender arms had to be chopped. had to file away part of the other side near the fender brace, to clear the caliper bolts.
eventually tetrised it in there, but the fork brace needs some more trimming as it's basically resting on the brake rotor.
doesn't look like much, but took forever. had to mount it to the brake side with the caliper in place, remove the right tube, rotate thewhole thing around and get the other fork leg in.
space is tight with the fender/fork brace. had to let a little air out and pinch the tyre going in, but it's fine once it gets in there.
the only thing that went smoothly is bobbing the fender. using a piece of card, i copied the arc of the normal fender. folded it over to ensure it was symetrical, then taped it where i wanted it cut. needed a little filing to smooth it out and take the edges off, but it came up good in the end. i guess this is the only real photo i have of new progress. i tacked the remaining section of exhaust on just for a look at how it may look (though i'm using a different tip, and wrapping the rest.

here's one with the completely unbutchered and still partially wrapped CB100/S90 front fender i'll be mounting to the rear. more or less in position, just needs the brace and arms removed and some mounting done.

in case anyones curious, we have seriously draconian laws for motorcycles. i legally need to have the rear fender at 45deg to parallel :(

i've got more time free next weekend. indicators, passenger pegs, chain,and mirrors are coming in.
but... i've picked up another project. or two, or three. another project bike (bobber), project car ('80 toyota corona, 2jzge sleeper?) and furniture my partner and i are restoring.
so many actitivities, so little time :(
 
That looks amazing man! I love that color combo, and I'm digging the fender idea. Nice.

I've ben tinkering on my little 100 as well....actually, I have been contemplating something a little unorthodox. First off, I picked up a pair of cb175 wheels for $80 shipped for bigger brakes. Guess what, they bolt right up. Second, I picked up a free CB250 motor with 4k on the clock that I am considering bolting in. I got the whole bike, and the mounts are surprisingly similar on these bikes.....they use the same swing arm, and the same sprocket on the rear....never heard of it being done, but it has definitely peaked my interest. Watching you progress is motivating man.
 
if i hadn't powdered the wheels i'd have hunted more :( but i'd probably lean the monkeybike way and get big USDs and dirt wheels.
i really don't like the fork on this bike, but at least it fits aesthetically

that's great! is the 250 a single or twin?
 
Yeah for some reason I haven't been able to find forks to fit that are upgraded....I did think about some awesome USDs, but I'm just not sure what to look for.

The 250 motor is a twin, but it's a stressed member motor. It is similar in mounting for sure, and the swing arm pars being the same part number from honda give me hope, because that tells me that sprocket alignment will not be an issue. The front motor mount is definitely different, but easily modified. The bike looks like this but it has a bent frame. Wrecked mess, but the motor is good to go. You can actually start it up. And it's a CDI motor.

CB_250_NDC_SUPER_DREAM_83-85_1.jpg


Thought you'd dig the idea man.
 
hey, that's my tank! :p

honda sprocket alignment seems to be:
if the rear mounts fit, everything is peachy.

as for forks, pitbike and those horizontal motor dirt bikes - they all have the same head stem. actually i think theyve got the same rear motor mounts too :p
they might need some work though, since the travel would be huge and the tubes might be too long (might not though, considering how small our scoots are)
theres a thread on the "other" board, but here's a pic of a selfbuilt frame based on an S90 with this kinda front end on it:
nooch1.jpg

(actually, that bikes got an interesting kickstarter too)

i'm gonna think about this again with my bobber build, but not sure if i can make USDs look right for a bobber. i need to source a front end less wheel at some point anyway :/
 
phew, it's been a while. i've had progressively less time to work on it despite final parts coming in :(
progress has been extremely slow. since my last update i've:
-given up on the rear fender (for now)
-mounted new 12-LED indicators
-mounted the stock chain guard after extensively cleaning it up
-cleaned/painted/mounted the hand controls and shortened the clip-ons accordingly
-mounted the new carb/trumpet (not entirely happy with the carb rubber length, but had clearance issues with both the tank and frame - might be able to bring it in an inch or 2 though, and i need to straighten the rubber a little so it doesn't point out at such a large angle).
ended up using the original cb125 manifold with a heater hose pipe. not ideal, but without getting some aluminium welding skills, i've no intention to redo it completely differently.
i still need to do the mesh/filter part, but i'll get around to it.
if anyones interested, the carb is a Keihin PWK copy. Keihin don't make PWK's in 30mm at all, but this carb ended up being less than $110 and it's amazingly good quality. i can't fault the quality at all. came with all lines/clips, set, and actually even uses a chrome D-slide which is an additional cost for real PWKs. really impressed...
-attached the throttle and made sure it works (zing! perfectly)
-attached passenger pegs
-shortened my clutch cable, attached it, but it promptly failed. it was an old cable anyway. this was a fail :( I now need to source an appropriately shorter cable.
-was tempted to shorten the brake cable (yeah, cable disc brakes.) but after watching the clutch cable fail, have reconsidered. apparently yamaha ttr50's had identical cables but only 32" - called and i can order one for $33 australian dollars. that's a win.
-got the motor 90% "ready" for first fire - being a chinese motor, it comes with horrible oil, crap plug, and clearances and tightnesses need to be checked. i took the opportunity to de-cheap the motor in the process slightly. used quiksteel (kinda like JB weld) to fill the writing, hit it with high temp black paint (3 layers) and then high temp clear. looked great, but when i stuck it in for the high temp cure, the quiksteel bubbled and it looks shit. more in line with the bike than the original look though :)
I say i got it 90% ready because I had to rush out the door when i was reattaching the clutch cover. so i haven't replaced the oil or attached the cover.
-mounted a fuel filter and fuel lines, but the filter is huge and ugly so i'll either hide or replace it. it's taking up precious electronics space at the moment, kinda directly underneath thte tank mounting tabs on the frame.

so in other words, i've got about an hour ahead of me before i can mount a replacement clutch cable. brake cable, then i can wire it up for a test fire and run :) hoping for this in the next two weeks, but i have been slow :(

here's the mandatory pic dump! :

 
can't wait to see it with the seat, love your idea for it. this little bike is going to be a blast!
 
Sebatron, I was browsing around on ebay a couple days ago and came across what appeared to be a hydraulic caliper for a later model CB125 (can't remember the year). Surprisingly, they were selling it for $10 or something. Don't know if it'll help, but just wanted to let you know.

Bikes lookin great BTW!
 
i considered the hydraulic swap earlier on - honda cg125s sometimes came with such brakes. also thought about using one off a scooter, and now i've got a complete caliper to lever 4 piston set off another bike (got 2 actually, off what's basically an 82 vt500c custom), i've thought about that too.
i can't be bothered with the hand controls anymore. i'd planned to change the switches completely, but couldn't find anything i liked, so i've stuck to the standard equipment.

mind you, once i get it rolling and i test it out... if it sucks ass, i won't care, i WILL upgrade it.
i've been at this build 7 months now. i'm letting go of obsessing over the really little things because at the end of the day, the build's always been on a strict, strict budget, both financially and timewise, and it's never going to be a show bike. or anything but a fun light thumper :)
 
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