Custom bike build

[aramis]

"We're all born different, so why would we ride generic bikes"

(some random dude at flea market)

 

Here should be some catchy title... 

...but there won't be one, because I'm an engineer, not a poet.

 

Disclaimer for US bikers - I know 125cc isn't considered a "real bike" in US, but here in Europe it is the best ride I can get without getting bike-class Driving License. And on top of it, getting a license is way more money and hassle than in US. So, no h8 pls.

 

First, some backstory: building a custom bike (or just having a motorcycle) is something I had on my mind for years. One time (I guess it was like 6 years ago) I almost started a project (not precisely caferacer, but custom for sure), bought bunch of stuff (bike in parts, couple motors, whole lot of random stuff) but I got overwhelmed by too many ideas and options, decision paralysis kicked in, I got disheartened... and finally dropped it entirely. Just sold the stuff on local Classifieds portal. 

 

This time I approached the topic differently. I got the bike in good condition (my first two-wheel ride since childhood when I had a moped), rode it as much as I could, and now - as the weather doesn't allow for riding anymore - it is time to take it apart and start tinkering  My goal is to get that cafe racer look and feel. It may be a fad and I'm jumping on the bandwagon, but it pleases my eye so be it. 

 

The patient:

This is the looks the day I bought it. 

It's Chinese rip-off of 90's Suzuki GS125, with engine being (again) Chinese rip-off of Honda CG motor (OHV version). 

 

As stated above, it's 125cc, so not really a good cafe racer material. More "cafe" than "racer", but I bought it as a toy, and I want to play with it.

 

I already flipped handlebars upside down to get more aggressive riding position and put headlight and speedo/rev counter cluster lower (for looks). And nix the hideous luggage rack. 

This alone got me some "pouncing" look compared to the original.

Spoiler

 

There was more mechanical tinkering, but it all was just maintenance stuff (changing fluids and a spark plug, cleaning/lubricating chain, carb and valve regulation etc).

 

Story mode OFF.

 

 

 

Lately I decided to play with GIMP (still learning ) and ended with first rough sketch of my "project": 

 

There's lots to do. To be honest, I think there isn't one component I would left unchanged (or replaced). Quite overwhelming . But when split into smaller tasks it looks way less scary and even doable.

 

The most intimidating stuff is frame conversion - I need to cut the red part away and weld new subframe in green position. This scares me the most because it's structural stuff. 

But the subframe modification is a must on any Suzuki of the era, as they all had this middle section lowered. That's why most small cafe racers are based on Honda CB/CG, which had flat frame all the way. But I have Suzuki clone and WILL deal with it.

 

 

There's whole list of stuff:

- shortening front forks

- elongating rear shocks

- frame mod

- removing all the stuff on the back, cutting frame and welding in tail hoop, 

- fabricating new register plate bracket and minimal fender

- replacing fuel tank with Suzuki TU-X one (not very cafe-racer'y, but I love it's shape)

- fabricating new seat with tail hump/cowl (not sure if I want fully upholstered one or just fiberglass pan with cowl and seat cushion on top of it)

- cleaning the central triangle by repositioning battery and the airbox (I'm not a fan of pod filters)

- fitting all the electrics in some sort of tray under the seat (or maybe I'll manage to squeeze this mess under the tank making place for custom airbox?)

- exhaust... argh  

- installing clip-ons in place of original (now inverted) handlebar (I was considering Flat/Drag Bar or Clubman style, but after making models and trying them on it didn't look good)

- getting rid of gators from the front fork

- replacing the speedo cluster for single digital one (already have several candidates, made models of them and will try on to see how will it look like)

- replacing blinkers and tail light with smaller, cleaner LED ones (I may fit tail light into the seat hump/cowl)

- repositioning ignition switch under the tank, to clear up the triple tree

- surely much more stuff I don't recall at the moment

[aramis]

Today I wanted to start disassembly. Did bit of work on the back and realized lots of work would be done kneeling - no fun for me. And as this will be done in spare time over the winter, it may take some time. 

 

So, after short consideration, I decided to make a work table. It will be simple bench durable enough to hold bike's weight, plus mine when needed. Nothing fancy like those lift tables on the internet... not this time

I searched around the house, got some beams, some boards, did the cutting and put it all into basement. 

 

 

The cardboard on the floor is where the table will be placed. It will be 2m x 60cm and 40cm high (roughly 6' x 2' x 1'4''). This allows me to sit on a stool when working on lower parts, and still reach everything higher. 

 

I will put it together in a day or two and get to actual work then. 

[ladymorella]

Looks like quite the project

[aramis]

I managed to put the bench together and fix the bike on top of it with a simple wheel vise. Now the stripping continues  

 

 

[aramis]

I started disassembling the front. The first thing was to deal with the spaghetti in the headlight. Every plug and it's corresponding socket has been marked with a number, and as a cross-reference I wrote down which wire went where. 

 

Took off gauges, mirrors etc. 

 

Now, as a first try-on I put my "model" speedos to see how they fit. I'm pretty sure I'll use one of those, but can't decide which one yet. So I printed out their faces in scale and glued on some plastic cans that were proper size. 

 

What do you think - which one looks better?

 

 

or 

 

Smaller one is more minimalistic, but requires me to fabricate indicator panel somewhere (high beams, blinkers, neutral gear and maybe gear indicator). And it has mechanical speed input, so I'm afraid it might be prone to false readings (seller couldn't tell me if there is any calibration). Here's one on the internet: 

On the other hand bigger one is, well, bigger, bulkier etc. But it has all the indicators built in and the speed is taken from electronic sensor, so it has the calibration for different wheel sizes. And the link.

 

This is of course very early concept, it might change as I go, but I think I'll go with digital. I love analog gauges, but having both speedo and tachometer would mean having two "clocks" and I don't want that. Digital one can squeeze more options in one case. 

 

As of plans - the handlebar will be replaced with clip-ons and bulky blinkers will step aside for smaller LED indicators. Headlight will probably stay, but I will need to fabricate different brackets for it, as the original ones interfere with clip-on assembly. This way I will clear the top of triple tree and upper fork area. 

[aramis]

Umm... yeah...

 

Anyway

 

To see how it fits I installed my clip-on handlebars (they are to be cut in length later), and just to see the difference I put on my clubman-style handlebar PVC pipe model. 

 

 

Honestly, I think I'm so afraid of cutting the frame, I will do anything to postpone this. I won't fight my fear yet, will go along. Next week or so I plan on making a rear shocks spacers to raise the tail about 3-5 cm, and put in spacers into front fork dampers to bring the front down approx. same amount. This should level the frame - the effect I'm after.

 

After that, there will be no excuse - I will finally start working on the frame.

[aramis]

 

Front disassembled.

Plan for the week - disassemble forks, clean, add lowering spacers, maybe cut springs, assemble and put new fork oil in. 

Make rear spacers for rising shocks, assemble it all to see if frame got levelled. 

 

If frame will be levelled, start planning on cutting and new subframe fabrication. 

[aramis]

First front leg disassembled, damper rod measured.

 

The spacer bushing needs to be dia 15mm/22mm and 50mm long. I won't cut the spring yet, firstly because I had some sag in the forks, and secondly to add a bit of preload. If it will turn too stiff, I always can cut later. 

 

And as a curiosity:

This is fork oil I drained. It looked like metallic paint   

[aramis]

Busy week at work, no time to make the spacers. For now I will use some scraps for substitutes and will test if frame line feels proper. 

[aramis]

No photo as it was late evening and I wanted to just get it done.

 

Turns out raising tail 5 cm is perfect, but lowering front 5 cm is too much. Bike ended tipped too much, and it felt like childs' bicycle when I was pushing it... so looooow.

 

I guess I'll shorten front spacers to 3 cm and give it another try. Not cutting springs yet was very good decision  

[aramis]

Here's how it looks like right now:

 

Fine for me with 3cm lower in the front and 5cm raised in the back. The middle part turned out horizontal, what I was aiming for. But this gave me unexpected issues with the chain - it now rests flat on a frame support just behind the engine, so I'd need to either use some slider (not sure would it work) or cut the support part and weld it somewhere else. And on top part of the loop, the chain rests on the swing arm, which again needs either slider or repositioning swing arm axle. 

 

I'm considering removing back risers to avoid chain issues and weld new seat subframe at the angle to existing one instead raising it parallel. 

 

Or maybe raise the tail just 2 or 3 cm instead of 5? Gotta experiment. I really like this perky back look  

[Dilnad]

Slow to notice this post so sorry....

 

 

Disclaimer for US bikers - I know 125cc isn't considered a "real bike" in US

This is an ongoing item with snooty bikers but doesn't apply to all of us. Many bikers wont give "The Wave" to scooters and mopeds because they aren't real motorcycles. Then their is the sect of us who don't have Harley's and attitudes. We respect all cyclists. Hogs, Mopeds, Scooters, classic 125cc bikes, and bicycles. If you're in the wind, you're in the wind my brother. you deserve the respect, and the camaraderie. 

 

Don't pay any attention to guys on sweet bikes who don't respect you. They also have sweet bike loans. You own yours  

[aramis]

Don't be sorry, you've found it. I'm happy for any attention this topic gets  

 

Thanks for kind words, luckily here in Poland most bikers treat each other decently. We don't have old "Harley boys" to scorn everybody else - the few motorcycles available after WW2 (during Soviet occupation) were mostly 125's and 175's so our biker ancestors were raised on quite humble base. Of course there will always be this douche Gixxer/'Busa boi, but they are rare  

[aramis]

After couple days of thinking and fighting myself, I decided I'll leave the tail at factory height (for now).

 

Raising it even 2 cm means I need to add extra lot of work sorting out "chain-sliding-over-frame-parts" issue. I COULD do it, but I decided not to (at least not now). This is my first such project, and I don't want to get too greedy and ambitious. If it would be my second bike - sure, I could let it sit on the workbench all year long. But I want it road-ready for spring, so I need to constrain myself. Firstly I need to focus on what's crucial, and leave bells and whistles for later.

 

So, I'm off to creating new subframe template out of PVC piping before I start cutting steel. 

 

This is where new subframe will be. Clean and level when bike stands on it's wheels. Top of the pipe will be flush with bottom edge of the tank, and the seat will rest on top of it as an elongation of this edge. 

 

The tail will be cut just as white pipe ends and seat loop will be added. Loop will have a slight bend upwards, to mirror the curve on front half of the fuel tank bottom, basically forming wavy line all the way. At least that's the plan  

 

The next problem I overlooked earlier is tank rear mounting point. In this configuration it is quite high (around 5 cm above subframe), meaning I will need to create some smart shape of the seat to cover it. Maybe something along those lines, where seat cushion "creeps up" on the tank?

 

But this is to be dealt with later. First I need actual subframe to rest the seat on  

[aramis]

Damn the thought process...

I don't like the white pipe position. I will raise it  ~20 mm (it's diameter) up, so the bottom of the pipe will follow the bottom of the tank (the subframe front will hide under the tank). This way, when putting the seat on top of the frame (without seat sides "hugging" the frame) I will need to hide only 3cm of tank mount, not 5cm like now. Then, the seat can be thinner, which is good for the looks. It'll look somewhat like first picture (with black seat) in prev post.

[aramis]

Okay, I just got an email form Distinguished Gentleman's Ride (charity event I plan to participate) that the ride is planned for May 23'rd next year. This creates a deadline for my bike to be road worthy. No surprise I hope to finish it (and of course - ride ) earlier, but this date is HARD LIMIT. 

[aramis]

Today I finally crossed the Rubicon. The only way is forward.

Spoiler

 

[aramis]

YAY! 

The new stuff arrived!

 

Speedo with control indicators, tachometer and some other gadgets, and set of LED mini blinkers. Those tiny bits flash surprisingly bright, even more I was expecting. But that's good, they are supposed to be visible  

[aramis]

New subframe is under construction. Sadly, two places turned down my query for bending the tail loop. Looks like I need to do it DIY style.

 

Apart of loop, new pipes are already cut and formed, waiting to be welded. 

 

I learn to stick weld, but seeing the results I think it will be a lot safer to take all the parts to my work for our welder do the job for me. I will need to take engine out of frame, but as I planned on painting it, I would need to take it out anyway. 

[aramis]

Busy, busy, busy.

 

But decided to use my sick leave for crushed finger and get a grasp of electrical wiring. No schematic fits 100%, so I use some different ones and cut looms to trace wires and make my own schematic. When I get there, I will plan new wiring  as I plan on some changes in there.

 

 

[aramis]

Ordered some stuff and it came today. Ignition switch, fuel tank cap, rear led lamp, bar end mirrors. Slowly creating new wiring schematic - I think I'm about 60% done. One tricky thing was finding out pin-out of speedo (it came without any instructions) but I managed not to burn anything in the process . Couple youtube vids were helpful in what to search for, even though the wire colors differ. 

[aramis]

I know working on the project in scarce "free moments", having out-of-order hand, (etc., etc.) makes this customization slow. But I'm happy I'm getting some progress every now and again. 

 

And today's step is... Seat subframe bent and welded together! 

 

It may be a bit unorthodox approach to make the subframe on-a-workbench and then fit it to a bike - most folks on the internetz weld the puzzle together directly on a bike.  But I'm not good enough at welding, so I need to prep pieces at my place and then take to work for welding. As Teddy Roosevelt once said "Do what you can, with what you have, where you are." So I'm doing it  

 

Anyway - now I need to fit the front to the main frame tube, take pretty much everything out from the frame (for ease of transportation) and take it for final welding to work. While stripping the frame I plan to see what actually would be necessary to reposition swing arm axle.  I really liked raised tail look  

[aramis]

I have put together front forks with 30mm PA lowering spacers, cut the springs 25mm (to add a bit of preload), filled with 20W fork oil. Now they wait for test assembly. On some point I will paint hem black, but for now I'm not even thinking about painting - mechanical stuff comes first  

 

Right now I'm working on repositioning the swingarm axle. I wanted to use  footpeg mounting holes, but learned they are on different heights on each side

 

To make the axle properly aligned I made a jig to distance it evenly from old position (I assume original placement was... straight enough). 

 

And the amount of filing I did to even the holes' position (axle dia. is 14 millimeters):

 

Now I only need to make support washers and weld them on the inside to precisely position the axle, and make the distance on the inside to fit the width of the swing arm bushings. The welding will be done probably between Christmas and New Year, as there will be less work in my workplace - so I will be able to ask our welder to do it for me.

[aramis]

Welding done! Swing arm axle fixing points, seat subframe and supports  

 

 

I really love how the shape of side supports turned out and the fact all the internal supports hide behind frame tubes. This gives me nice clean line to fit the seat on.  

 

 

Next step - cut off old brackets, clean the tubes from old welds, get rid of passenger footpegs' supports. Sand all the rust off, put on primer and some paint to prevent further rusting.

On the front bracket I will make gas tank mount. Probably in form of two bushings, because I want as much free space for the seat cushion as I can have.

More towards the tail, between the side supports will sit an electric box I have already prototyped in cardboard. Now I need to fine-tune the shape and get some sheet metal to form it. 

 

[aramis]

Okay, frame clean-up done. I'm very happy with the lightweight feel of the tail section. Finally the bike starts to take its shape  

 

The only one thing left to weld is side stand mount I had to cut off when getting rid of passenger footpegs' supports. After that the frame will be done, or so I think. The last decision will be either send it to powder coating or paint it at home. Powder coating is expensive, but most durable against weather and mechanical damage. On the flipside, once the frame will be coated, I won't be able to easily modify it anymore. Any welding (and cutting or drilling to a lesser extent) will damage the coat in that area, which defeats the whole idea of durable paint job. Painting it at home will be more prone to damage and rust, but in need of a mod I can do it and then just respray the area.