1976 CB200T cafe build UK

cinch

Active Member
So this is my first ever motorcycle build. Having followed a number of threads on this forum that have given me a huge amount of inspiration over the past few months i figure its time to show you guys what ive been up to in my garage!

I started looking for an older 125 bike that would work with the cafe racer look, I soon narrowed down to the trusty old school Honda CG 125. Good old eBay threw up a suitable victim and to cut a long story short I am now the owner of a 1979 Honda CG125. It turned out to be a great runner and in pretty good condition considering it age.



 
Re: 1979- CG125 cafe build UK

So i started by stripping the bike down enough to get a rough idea of what it could look like, i flipped the handle bars for good measure too!



 
Re: 1979- CG125 cafe build UK

After considering how to get a cafe seat for the bike, I came to the conclusion that buying an off the shelf seat for a bike like this was far too expensive for the value of the bike, so ive set about making my own, initally looked at using the standard metal seat pan, but it weights about 4kg, so binning it for a lightweight seat is definately the answer, these bikes are underpowered already and need all the help they can get!

After reading up on it and watching a number of videos i decided to build the seat using the Buck /Mold/Finished Piece approach, some people shape a seat out of foam, fibreglass over it, and then cover the thing in filler to smooth it out, that just seems the wrong way to do it for and in the hunt for "Lightness" i wanted as little extra material as possible!

Forming the Buck:

Cardboard templates:





Then Transfered to 12mm MDF to provide a good structure, this was held together with a glue gun, it always amazes me how strong that stuff is!





The former was then filled with expanding foam, i may have got a bit carried away at this point, this stuff will stick anything to anything, pretty nasty stuff. The great thing is when it sets you can carve it into shape really easy. i learnt a neat trick of spraying water on it, it slows down the reaction making the foam denser. Less filling later on!




And cut down into shape, i used an old flexible ham knife for this, it did a great job!




Once finished i then cover it in cheap filler to bulk it out, then rough sanded it down and covered it in Stopper filler which is much finer and gives a great finish:




Then a good couple of heavy coats of highbuild primer, primer, and Top coat to give a good finish to made a mould from! Pretty long winded but the finish is worth it.







More updates to come!
 
Re: 1979- CG125 cafe build UK

Once the paint had set, i started to set the buck up to make a decent mold, due to the angles involved I decided to make a split mould due to the release angles involved, on retrospect i probably could have gotten away with a 1 piece mould but you live and learn:

The mould centre board was put in place to make a clean divde, held in place with clay, I also used clay to create location "lumps" so when the two halves come together they locate in the same place.



Then it was cover in a couple of coats of Bees Wax and several coats of hairspray used as mould release which worked a treat, after that it was coated in gel coat:



Then 4 layers of fibreglass and resin:


Once set the centre board was removed and the process was repeated, wax, hairspray, gelcoat, fibreglass:







And then the final moment, where you workout if you have cocked it up and need to start all over again!



Thankfully the two parts seperated and the finish was great. cue sigh of relief!
 
Re: 1979- CG125 cafe build UK

Once completely set, the mould was wet sanded down to 1200 grit wet and dry to remove any imperfections, bolted together, and the joint filled with clay to reduce seams on the finished seat. The mould got the release treatment - Wax, and a load Hairspray, then two decent coats of gelcoat, to give it a smooth finish, once this started to "Green" i started to layup the fibreglass, i think I did a layer of fibreglass tissue, followed by 5 decent layers of fibreglass Mat, im not sure how strong this will be but i guess I can always add more later if needed.






I release it from the mould before it has completely set as it was a bit more flexible and made life easier, once cured it was trimmed down to the finished product! all it needs now it fitting, and final finish :)



 
Re: 1979- CG125 cafe build UK

I had also be working on the tank along side the seat, as i got the bike so cheap, i figured I might as well go all out on it and decided to "Add" some knee dents, this involved beating the hell out of it with a rubber mallet, which was really satisying.

I tried marking up a template, but ended up just eyeballing it until it looked right:






Once i had the shape roughed out i stripped it back, if it wasnt for all the dents i would have just clearcoated the tank and left it like it was!




After a load of filling and sanding it started to take shape:





and this is what i ended up with - Tank and seat in high build primer.



 
Re: 1979- CG125 cafe build UK

The focus then shifted back to the seat, and how I was going to get a brakelight on the back, i looked a hanging a light under the seat, but it looked poo. I found a great little rear light off the back of a landrover defender, and set about recessing it in to the bike seat. I havent got many photos of the process here, but it involved using a carboard tube (Gravy tub) and a hole saw, i cut a hole in the rear of the seat using the hole saw, eyeballing it so it was level, then put the tube through the hole, and fibreglassed over it using it as a former. Then the usual filling and sanding followed.





High build Primer:


Primer:



finished rear light:





And I sprayed the tanks topcoat and buffed it out, not bad for rattle cans!

 
Re: 1979- CG125 cafe build UK

Bro! Your tails is SOMETHING ELSE! Extremely nice!
 
Re: 1979- CG125 cafe build UK

Thanks Juan, it's been a long time in the making!

This is the seat pan that I made, I was originally going to form it from aluminium, but decided to go either fibreglass in the end. It basically involved masking over the seat with cellophane and then glassing over the top, I added a couple of ribs in the seat pan for extra rigidity then covered it in two layer of foam, one hard, one soft. I also resined in some t nuts so fix it to the actual seat.



Oh and I got some really cool rear indicators


 
Re: 1979- CG125 cafe build UK

Good job mate, u must have done some glass work before

Looks nice an neat, u must b happy with that ;)

Wayne :)
 
Re: 1979- CG125 cafe build UK

So the final update before I get to to where I am today is the front end, in an effort to make the bike better I decide to use the forks from an Aprillia RS125 as I managed to get a pair for £14 which was a complete steal, the hardest part of getting the forks to fit was finding the correct bearings to use, CG125 bearings are 24 x 41mm, and unfortunately the Aprillia forks need a 25mm internal diameter, after days of hunting it became safe time say that no one makes a 25 x 41mm headset bearing.

I found a solution by purchasing some 24x41mm pitbike bearings, this are the non sealed split bearing type, I then had the internal diameter machined out a mm to 25mm making sure there was enough meat on the bearing cups.

http://www.mypurerush.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/p/i/pit_bike_headset_bearings_type_2_-_ot41_2.jpg








I think the bulkyness of the front end will balance out the size of the tail when it's finished.

I also found a 36 spoke front hub with a 20mm axle diameter to fit the Aprillia axle, this came from a 97 Honda CR250, I've polished up, when I get some spare cash I'll get a nice new wheel built, but for now I am a bit stumped on how to rig up the Speedo, any ideas?
 
Re: 1979- CG125 cafe build UK

Same forks I'm going with, nice size, I found them slightly shorter than the standard xs400 , how do u find them to yours, may give it a nice stance if its slightly down at the front :)

Wayne :)
 
Re: 1979- CG125 cafe build UK

So today I was gifted a cb200 engine! Great news as i love the sound of the honda twins over the singles, the only problem is that it doesnt fit straight into the frame.. as the scope of the project keeps bigger and bigger I figure why not give it a go

Honda_CB50_-Dream_Cafe_racer_Taimoshan_01.jpg


This guy has managed to squeeze a 125cc twin into a cb50 by what looks like bending the front arm of the frame out, and modifying the rear mount, I will have a proper look at this over the weekend, and post my findings, has anyone got experience with this?
 
Re: 1979- CG125 cafe build UK

So today I dropped the engine out other the frame, I love how simple these things are, it makes such a nice change from working on complex cars!

So after getting the 125 engine and cb200 twin side it was good to see that as expected the engine is much wider, but reassuringly it is not that much taller which is good news if I'm going to squeeze it into this tiny little frame!

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So this is what it looked like when I lined the frame up with the cb200 engine, it looks like it needs to open up about 60mm to allow it to fit.

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Re: 1979- CG125 cafe build UK

I went out and bought a blow torch this afternoon, and set about bending the front leg, I ended up heating the frame leg until it was red hot, then wedging a car jack between the leg and back of the frame, bending it until it fit.

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So on the first go I've bent it out a bit to far, but gotta start somewhere! I'll pull the leg in with some more heat and a ratchet strap once the rear mount is underway.

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So I'm going to have to weld in a couple of plates to pick up the lower mount on the cb200 engine, and some gusseting to make the frame a bit more rigid. But other than that I think we on to a winner.
 
Re: 1979- CG125 cafe build UK with cb200 twin conversion

Here are couple more photos of the engine in the frame. Still needs quite a bit of work but it is coming together.

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And a mock up shot with the tank and seat pan:

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Re: 1979- CG125 cafe build UK with cb200 twin conversion

So I had another pop at the frame today, out came the blow torch again and a ratchet strap to apply some force.

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So after a bit of back and forth, this is the result.. tadaa! Cb200 twin into CG125 single frame!

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It's only mounted on two bolts at the moment using the existing CG125 mounts, but this allows me get around the engine a little easier.

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Re: 1979- CG125 cafe build UK with cb200 twin conversion

And a couple of pics with the tank and tail.

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