Topic: [info/tips plz] - Little Honda - cb 100

[Brunow]

Does anyone has some thoughts about the "little" honda?
Cb 100 - cb 125. I recently found a old cheap bike witch i would like to have for around the town (café bike).

But it's hell lot of work to rebuild it. Is is easy to find parts? Some links? Everybody has driven it so...

Let's talk about Little Honda cb 100!


edit: added image

[nickjtc]

Stonking bikes, especially the CB125, which was hugely popular in the UK in the '70s. If well maintained the motors are pretty well unburstable (given, of course, a degree of restraint on the part of the rider!). I'm not sure what the spares situation would be now, but try Honda for consumables, as well as the usual sources, like David Silver Spares in the UK, and of course eBay.

The 125 motor was also used in the TL125 trials bike, which has achieved a degree of cult status, with prices to match. Motor parts are probably interchangeable, but be careful that anything labelled as 'TL125' will probably carry a premium over anything labled CB125.

[ofreen]

I have an '81 CB125S.  Some days I think it is the funnest bike I own.

[Brunow]

Stonking bikes, especially the CB125, which was hugely popular in the UK in the '70s. If well maintained the motors are pretty well unburstable (given, of course, a degree of restraint on the part of the rider!). I'm not sure what the spares situation would be now, but try Honda for consumables, as well as the usual sources, like David Silver Spares in the UK, and of course eBay.

The 125 motor was also used in the TL125 trials bike, which has achieved a degree of cult status, with prices to match. Motor parts are probably interchangeable, but be careful that anything labelled as 'TL125' will probably carry a premium over anything labled CB125.

COOL! omg never seen a tl125 before but it's sure a cool bike! (http://www.kaila.net/tl125/)

Hmm looks like a cool thing to mess around with!

[csendker]

I've got a CB175 that I'm rebuilding.  I considered trying a cafe or whatever, but decided to stick with the stock look.  I haven't had the pleasure of riding it beyond a lap or two around the block while sputtering, spitting and backfiring profusly.  I can't wait to get it running, it looks like it will be a ton of fun bombing around town as a high-milage commuter.  Don't think I'll try it on the interstate or for any big trips, but that's what my 550 is for.  Besides, I need a second bike to run for whenever I take the other down for service.

[crazypj]

Bore it to take a CB750 piston(145cc)
Most of the transmission parts from any year will either fit right in or can be modified to fit. you can fit 6 speed from XR185 or XR200 but it takes a bit of work. The made in China 150cc parts can probably be modified (forget name ?)
PJ

[HondaMan]

I want one of the 4-cylinder ones. Honda also made the 2-cylinder 50cc. I want one of them, too....

[oconnor]

I have the cb125. Side covers are impossible to find. Everything else is not too bad. Quite a few cb125 on Ebay lately, some as high as $600.00 complete and decent.

[Brunow]

I want one of the 4-cylinder ones. Honda also made the 2-cylinder 50cc. I want one of them, too....

twin 50's?
4 cil 125's???

whow

Too Big' TL Engine
There has been comment recently on oversize TL engines. I do not wish to unnecessarily prolonging the debate, but I would like to illustrate a point I made on the Message Board:

When overboring with the intention of using a CB750K2 piston the liner MUST be replaced with one of a larger outside diameter. I know that not everybody agrees with this, the implication being that the old liner will suffice. This is untrue, it will fail. Sometimes it is claimed that a 122cc barrel wont do but a 124cc barrel will. Again, this is untrue; both liners are of the same outside diameter and when bored to accept a 750 piston the wall thickness is left at 0.018" (less than 0.5mm). Enclosed is a picture of a standard barrel bored to take a 750 piston. As I bought the bike in this condition I cannot say how many miles or hours the engine ran for before it failed. However, it does not appear to have run for long as the piston is relatively unscuffed.

What is not clear from the picture is that the crack runs a quarter of the way around the liner at the line where it emerges from the alloy barrel, then migrates to the bottom edge. Even where the liner isnt cracked it can be squeezed oval between finger and thumb. In addition, because it is not possible to put a 'lead in' at the bottom of the liner there is a high risk of breaking the piston rings on assembly. So don't ruin a new overbored engine by not replacing the liner.

kinda cool!


Yeah i heard about the chinese 150's they are good for a cople of months... then you get the diffrence bitween honda and chinese crap.
it's better and cheaper at the end to rebuild an old honda! (and more fun!)

[medic09]

CB100...great memories!  First real motorcycle I rode (after little Honda 50 and 70 and Rupp Roadsters).  A HS buddy owned it, and sometimes we'd ride two up on that little thing to our after school job.  It was a whole lot of fun.

As my father would say: "use it in good health!"

 

[crazypj]

USE the 750 liner...