Engine rebuild- '78 Honda CG125 'Retro Supermoto'

[Fungus]

So, some of you may remember my cg125. After a couple of years arsing about with it i thought id do it properly (I'm 18 now so i need a nice little bike ride around on.

Been building it over the last 6 months or so, so expect a load of pics.

Enjoy.

Here's the bike when i first got it. It was pretty tidy, with 7k on the clock, but a lot of unexpected rust and electrical problems.





So, thats how it stayed for a while, apart from a silly exhaust. But a little while ago i thought i might as well make something of it.

So, here it all mocked up, trying to get things to look right. The wheel had already been powdercoated, with stainless spokes and brand new tyres.



Cut down front mudguard





I wanted a trials-style rear hoop on the frame to go over the mudgaurd, in those pics its just mocked up and not attached. So i bought some steel bends and got busy

[Fungus]

I also made a plate to sit under the seat are of the frame. The idea being that this would go under the tubing, and the seat would go ontop of the tubing, leaving space inbetween for wiring. Sounds wierd but you'll see.

This plate would also hold the ignition switch, so i set about modifying the original barrel mount.







The plate was then cut out and the modified mount bolted on





And tabs with captive nuts welded to the frame

[Fungus]

To clarify, this whole part mount up under where the seat goes;



So, with the frame all mocked up and all the welding done, it was sent off to Maldon Powdercoaters along with a few other bits and bobs. When it got the fun bit started-



My brother lending a hand here... So the swingarm and shocks etc were put on. But meanwhile, i had also been busy with the engine, stripping it right back to the cases and painting everything.

New cylinder arrived and was painted later on



(sorry for lack of build pics) The engine came out pretty nice really



Fins were polished...



And put in the bike

[Fungus]

Sorry again for the lack of pics, I'm just piecing together the story with the ones I can find.

Modified the stock numberplate mount, and made an aluminium plate to go over the top of it



The ali plate also acted as a mount for the BSA rear light unit



The stock modified mudguards were blasted, welded up and painted satin black. The stock exhaust downpipe was welded to a universal short megaphone and wrapped;



And finally, (sorry for the instagram filter, like said I'm just finding all my pics), all bolted on a looking good. bit of white lettering to complete the 70's look. Glad I went for satin black on the mudguards instead of the 'chrome' powdercoat used on the rims, I love the satin against the gloss frame. the exhaust is mounted with a little bracket I made out of some 3mm steel, drilled and painted satin black


I know there hasn't been much mention of the tank but you'll see in a week or two the tank in this picture is just a spare I had, don't worry haha.

[Fungus]

Lastly for today, a seat base was made from 4mm ali;







and drilled/tapped so that bolts could pass through and be bonded on. This way, the seat locates itself and the bolts pass through the holes drilled in the frame. They are then tightened up with nylocks



The seat was then sent to Andy Nickson, who is local to me, for him to work his magic.

Here it is;







Heres a closer look at the plate/panel that mounts underneath. There is a gap between it and the seat, where the scratch built wiring loom runs.

[dodgerover]

Nice tidy work there, wanting a rear trials type frame loop made me laugh - the number of those that have been cut off trials bikes I've had and flat plates put on to locate the mudguard....

[gazjon]

That looks epic. One of my favourite bikes I ever owned. Can't wait to see a vid of it on the road

[PHUQ]

I always wanted to do something along those lines with mine (my first bike). Wish I'd stuck with it now 'cos that's looking ace!

[Fungus]

Thanks for the kind words fellas.

CG's are such great little bikes and actually have a load of potential. Its got a lovely growl too it now with that pipe and carb.

[PHUQ]

These early ones do seem to have quite a distinctive sound. I loved mine...

[Fungus]

That's nice and original looking! I love the stock airboxes they had with the mini tool kit underneath.

Tempted to buy another to rebuild as a proper cafe racer

[monkeytennis]

Hey man, this looks really great! what a cool way to freshen up an old bike. It will look great on the go!

[Gas Works]

really impressed with this. My first bike was a CG125, had great plans for it till somone had it away one night.

[redratbike]

That looks a big carb? Is it a mikuni pitbike one.

[Fungus]

Thanks fellas I actually rode it for a few months but the other night the stator plate packed up so its all in bits for a 12v conversion and i few other bits. Wish i had some pics, i'll get some up soon.

The carb was a pwk28 replica, ran like sh*t because the vacuum from the cylinder would hold the slide open when i let off. Using a mikuni vm26 now, its great.

[redratbike]

Oct 11, 2013 21:30:14 GMT Fungus said:

Thanks fellas
The carb was a pwk28 replica, ran like sh*t because the vacuum from the cylinder would hold the slide open when i let off. Using a mikuni vm26 now, its great.

thanks for that ...i have a 250 twin with knackered carbs ,,,clened them through but still rough running i'm thinking a pair of VM26's to get it sorted as they are quite cheap

[Fungus]

Oct 24, 2013 11:33:09 GMT redratbike said:

Oct 11, 2013 21:30:14 GMT Fungus said:

Thanks fellas
The carb was a pwk28 replica, ran like sh*t because the vacuum from the cylinder would hold the slide open when i let off. Using a mikuni vm26 now, its great.

thanks for that ...i have a 250 twin with knackered carbs ,,,clened them through but still rough running i'm thinking a pair of VM26's to get it sorted as they are quite cheap

they're a pretty good carb tbh, the Molkt replicas arent too bad either at £25 quid each!

[Fungus]

If anyone has a spare stator plate and/or flywheel i will buy it.

Need to get this running again.

[93fxdl]

You probably already have tried these people
www.davidsilverspares.co.uk/
but if not I hope it helps. Used them a few years ago and found them very helpful
Ttfn Glenn

[composimmonite]

Make sure you have a legal number plate for MOT time. Nothing more frustrating than to have a fail on something so petty but those are the rules - reflective only for your year bike. Also strictly is should be as vertical as possible so that is another area where a potential MOT fail.
MOT testers manual section -
www.motuk.co.uk/manual_630.htm
BTW it's also a reason for Police to pull you if they are in the mood.

Paul h