Introduction: Give a New Life to an Old Motorcycle! How to Build a Cafe Racer

About: I always loved making things since I was a kid! I currently make a lot of DIY drones and love 3D printing! I'm also into skateboarding, motorcycles, electronics or anything that can be home made :)

Hi everyone,

In this Instructable I'll teach you how to give a whole new life to an old motorcycle that deserve to be taken care of, and probably save it from ending in a junkyard.

How? by turning it into a Cafe Racer!

The goal of this Instructable is to show you an "easy way" for a cafe racer project and let you know that everything is possible, even if you don't have a workshop or power tools! all you need is to be creative in your project, there is always a way to achieve it!

I will also give you some tips and tricks to make things easier when making a cafe racer project such as how to easily paint motorcycle wheels, how to clean an exhaust header etc.

In my project, I had a limited budget, and no workshop at all, just a parking spot in my basement, without any power plug, yet this didn't prevent me from achieving my project. Many people will tell you that an angle grinder or a welder is a must have for cafe racer project, this is not true, a $5 hand saw will work just fine, it'll even make cleaner cuts than an angle grinder.

I was dreaming about making this project for a long time, but I did not have the space in my previous apartment.

The whole project took about 1 month, by working on the bike about 2 to 3 hours per day (coming home from work). So around 50 hours, which is pretty quick.

The bike I based my project on is a 1994 BMW K75 RT that had 138000 km.

Difficulty : medium to easy if you are familiar with mechanic. There are really no particular skills needed for such a project, you can learn everything in the process :)

Main Basic Tools needed :

- A tool box with a complete ratchet & socket set

- A hand saw to cut metal & wood

- A jigsaw might help

- A torque wrench for the engine/drivetrain bolts, it is important not to over tight those

Step 1: The Full Build Timelapse Video!

I have recorded almost all of the work I've done on the bike with my gopro in order to create a full timelapse video of the build :)

So here it is, this video features every step of the Instructable, you can either watch it before or after reading all the steps.

Step 2: Acquire an Old Bike You Like

The very first step is choose the bike you want to base your project on. This is the most important decision of your project as everything will depend on it.

For cafe racer project, many bikes from the 80's to early 90's are very good base bikes, you'll find a ton of article online about which bikes are the best for cafe projects, the most famous one being the Honda CX 500, BMW R series, Yamaha Virago's, etc.

However, the most important thing in my opinion is to find a bike you like, where you can see its potential.

For example, I chose a BMW K75 because I loved the look of the engine, its 3 cylinder configuration is uncommon, makes a beautiful noise, and the huge crankcase and camshaft covers on the sides have a retro look I find amazing, I also love the shape of its fuel tank. Moreover, this bike is pretty easy to find and not too expensive, so finding a good used bike wasn't too difficult.

Since the goal is not only to create a cafe racer bike, but also to give a new life to an old motorcycle, it is important to choose the right one :) I think that motorcycle are beautiful things, each one having its own story, so choosing an old bike that deserve to be taken care of, and give it a second life is a very nice feeling :)

There are many factors to consider when choosing yout bike :

- Rarity, old bikes tends to be rare, and with the cafe racer trend going on, they are getting more and more expensive. Choosing a bike that is not too rare, means that you'll be able to find some good one cheaper, and this is important.

- Condition. Don't be mistaken here, I've said before that I was looking for a bike that needed to be taken care of, but the condition of the bike is very, very important. It is always better to acquire a bike that runs great for few hundred bucks more, than a bike you can't ride at all for cheaper. I tend to avoid bikes that are not in a riding condition, does not start, or that you can't even test ride. You never know what you're gonna find and engine repairs are by far the most expensive ones, so it's better to get a good running bike, which had a good maintenance, but whose aesthetics or body parts might not be perfect, making it great for a transformation.

- Don't be in a hurry. It is also tempting to get a bike you like, thinking "wow this is an amazing deal" but do not be in a hurry, take your time, check the listings of the bike you want to acquire for few weeks, and keep in mind that new bike for sale will come up every week, just take your time to find the great deal :)

So, the bike I got, the '94 BMW K75 RT was running fine, although it had few oil leaks at seals, I knew that this was not a big deal and was just caused by the full synthetic oil the previous owner used (instead of mineral). I planned to change all the engine seals anyway.

So the engine was fine, the clutch and gearbox too. But the frame and body parts of the bike needed attention, many parts were corroded from riding during winter, or needed intensive cleaning. This was the perfect bike for me, as I didn't plan to keep 80% of the body parts.

Step 3: Strip It Down!

Once you got your bike, the very first step is to strip down!

Basically, remove everything until you get to the frame of the bike. Why? Because most of the parts like fenders, seat, fairings etc. will not be part of the final bike, and can be sold for money. But even if you wish to keep specific parts, it is best to remove them for cleaning & renewing.

Having the bike all stripped down will also make basic maintenance on the bike much easier! It will also allow you to spot eventual problems like rust points etc.

When I stripped my K75 down, I notice that the sub frame and and fork were pretty corroded, so I had to fix this;

Stripping the bike down takes some time but is not difficult, you just want to make sure to label every wire you unplug (turn signals, horn, tail light, etc.) which will make you save a lot of time when building the final bike.

You can easily find service manual for motorcycle online and they are free most of time. Just google " Bike model service manual", for example in my cased I googled "BMW K75 Service Manual" and found full PDF manuals for free.

Service manual can be useful when stripping the bike down to help you remove some parts, or for the basic maintenance like oil change because they'll include the recommended oils, and tightening torque of all the bolts.

Step 4: Renew It! Make It Look Fresh and Young Again

The real job starts now! It's time to give the bike a second life!

Basically, you'll want to make it look and ride like a new bike again! Fix everything that needs to be fixed, repaint things, change parts, etc.

Don't worry, bike maintenance is actually easier than it sounds!

For example, draining fluids (engine oil/ gearbox oil, etc.) is often as simple as removing a bolt on the bottom, drain the oil, putting the bolt back on, and filling fresh oil from the top! You might have to change the oil filter, but it is also as simple as unscrew it and screw a new one on after oiling its seal.

There is just one key rule to follow: tightening torques, they are very important! especially on engine bolts, you do not want to break a bolt in your engine or crush on a seal. If you are wondering if the tightening torque is important on a bolt, just remember this: if there is a seal on the bolt, or if the part held by that bold has a seal, then it is very important to have the right tightening torque. If the bolt is too loose, you might have leaks, if the bolt is too tight, you might either break it inside or crush the seal, damaging it.

As for renewing rusty or old parts, it is often as simple a removing them, thoroughly sand them to remove rust or impurities, and painting them. Spray paint is fine if it is the right pain for the right surface: use hot paint for engine covers, use plastic or aluminium primer if you are painting plastic or aluminium etc.

On my project, here is what I did :

On the engine maintenance side, I changed all the fluids : engine oil & oil filter, gearbox oil, final drive oil, renewed all the seals, flushed the coolant.

The ABS was not working and I suspected a low battery, so I removed the battery, charged it up and everything was good again! ABS and battery.

On the bike's body, here is what I did :

- Sanded and repainted the engine covers, changed the cover seals too

- Sanded and repainted the sub frame

- Painted the wheels black and greased the axles

- Changed rusty bolts with brand new stainless steel ones

- Removed all the rust from the fork and polished it

- Removed all the electronic parts (ECU, etc.) to clean them

- Lubed the clutch cable with silicone

- Few other stuff like changing the brake pedal etc.

- Thoroughly cleaned that exhaust header that was covered with years of dirt and did not looked great at all! Here is another tip in order to clean steel exhaust header: use some Harpic powerplus MAX WC cleaner (in contains chloride acid!). Apply some on the exhaust and wait 10 time, the acid will clean the metal from rust and dirt, then wipe everything off and repeat 3 to 4 times for a brand new steel exhaust! But make sure to wear gloves and a mask, this thing is nasty.

- Thoroughly cleaned the bike (frame, fuel tank, engine intake covers...) and polished and protected them with silicone spray so hey look brand new again.

I also plan to have the fuel tank repainted by a professional and will do it soon!

Step 5: How to Easily Paint Motorcycle Wheels

Now, I've added a step only for this because it could also be an Instructable by itself: How to easily paint motorcycle wheels!

Painting wheels can be a long and tedious process, unless, you go this route!

Here is a step by step process on how I painted my wheels :

- Start by removing the wheels & tires from the motorcycle

- Thoroughly clean the rim, and when I say thoroughly, I mean it, clean it like if you were going to eat on the rim! You'll want to remove as much road grim as possible! this is what took the longest for me! Use some wheel cleaner & degreaser and make it look as clean as possible.

- Sand the rim using some fine sandpaper, you can start with 400 grit then work your way up to 1000. Wet sanding is better.The sandpaper should remove the road grim that didn't go off when cleaning the rim. Once sanding is done, clean the rim one more time to remove the dust.

- Fully deflate the tire and mask it using some playing cards! this is the trick here! The idea is to slide the cards between the rim and the tire, this way, the masking line will be very clean and the cards are easy to remove once the paint job is done! When all the cards are in place, you can tape them to the tire to secure them in place. If they are bearings on your wheel hub, mask those too with some basic masking tape. Do it on both sides of the tire as we're gonna paint both sides at once.

- Lay the tire flat, and start painting it with a spray paint, you can spray one side, then flip it to spray the other side without waiting for the first side to dry as it won't touch the ground! For the paint here is what I did :

- 2 layers of aluminium primer (grey color)

- 3 layers of black wheel special paint (more resistant to scratches)

- 2 to 3 layers of clear varnish to protect the paint. Make sure to wait at least 24 hours before the last coat of paint and the first coat of varnish.

- Once everything is dry, remove the playing cards by pushing on the tire and pulling them off. You can then inflate the tire back and mount it on the bike!

Congratulations! you have brand new looking wheels on your motorcycle for less than $50!! :)

Step 6: Design Your Project and Get the Parts

Now, this is one of my favorite step, the step where creativity is the key! the time to design your bike and how you want it to look!

Basically, what we have right now is a motorcycle with a bare naked frame, just a fuel tank, an engine and some wheels. Creating the bike from this point is totally up to you now!

You can either go with a small seat for one person, a large seat to fit two people, some clip-on handlebars for a cafe racer look, or some flat bars for a flat tracker look etc...

Everyone will prefer different look for their bike so just think about it and go for your favorite look! You can find a ton of inspiration online or even use Photoshop to check how you want your bike to look.

There are 2 main types of look for bikes :

- The Café Racer, the cafe racer bikes usually have low, clip-on bars for a racing stance on the bike and a one seater seat with a seat cowl on the back. Most of the time, people will want to remove as mush as components as possible of their bike and have an area where you can "see through" the bike under the seat.

- The Scrambler look, scrambler bikes have all terrain tire allowing them to ride on dirt, flat bars but not clip-ons, and a flat seat that can sometimes accommodate 2 people but no seat cowl at the back.

There are others looks and variants too like the flat racer / tracker, brat style etc.

When you have a clear idea of what you want for you bike, you can start choosing the parts you like, especially the seat (there are a ton of different seats out there) and order everything!

Do not be too ambitious for your project! Sometimes it is tempting to go for a super complicated project, with frame/suspension modifications, full intake modifications or even custom made exhaust etc. in order to get a sick looking bike. But in my opinion, it is better to go for something a little bit easier, that you are sure to achieve, than going for something that is way too complicated, and not being able to achieve it, or achieving over a year...

Most of the unfinished cafe racer projects for sale are because people wanted to do something way too difficult, do not make that mistake, go for something you know you're able to achieve. It'll always be possible to make more modifications later on ;)

In my case, I wanted to go for a cafe racer look with a low seat cowl that is only partially upperholstered.

To achieve the look of the bike I wanted, here is what I did :

- Installed a partially upperholstered cafe racer seat, painted in red to match the fuel tank. I have integrated a led strip brake light on the back of the seat along with turn signals and a license plate holder.

- Changed the old, rusty exhaust for a new, stainless steel exhaust

- Installed clip-on bars and lowered the front Triple clamp by 5cm to lower the front end of the bike and mount the clip-ons. I've also changed the grips

- Installed a round headlight and turn signals on the front

- Changed the stock instrument cluster for a smaller aftermarket speedometer & tachometer

- Made some black side panels from aluminium and integrated the stock temp gauge in one of them.

- Installed some fork boots

- Installed some bar-ends mirrors

- Relocated the ignition switch from the handlebars to the right side under the fuel tank

- Few other cosmetic changes or add-ons to complete the cafe racer look

Step 7: Fit All the New Parts on the Bike: Be Creative! There Is Always a Way!

Now that you got all the parts you need for your cafe racer transformation, it's time to fit them on the bike.

The cafe racer/scrambler parts (seat, handlebars, headlights, etc.) are universal, so they may not be simply bolt-on parts, they might need you to create custom mounts to install them.

Usually, parts like clip-on handlebars, headlight with fork bracket, mirrors, etc. will fit without problem and will not require any modification as they clamp on standard motorcycle parts like the fork tubes for example. You just need to be sure to order the correct universal parts for your bike. For instance, my bike has 41mm fork tubes so I got 41mm clip-on bars (they exist in multiple size).

However, parts like seats will almost always needs you to create custom mounts in order to install them. It basically have 2 or 3 mounting bolts, that will not match with anything on your bike frame. So what I did with my seat is that I made a support for the seat from a 18mm thick plank of wood, with mounting holes to bolt on the frame on one side, and holes for the seat to bolt on on the other side. This solution allows me to easily mount and remove the seat from the bike, but also makes the seat stronger as it has the same shape as the seat and allow it to rest on that wood plank.

Moreover, this piece of wood under the seat allowed me to mount easily mount turn signals and license plate holder by bolting them on it. Same goes for the Led strip light, I just stick it to the wood plank.

I also made a lot of custom 3D printed parts.

My 3D printer was very useful in order to create mounts or enclosures for smaller parts like turn signals, speedometer, ignition key holder when I relocated the ignition switch to the side etc.

What I did is I measured my parts and mounting holes on the bike, then 3D designed supports using Autodesk 123D design and printed them. This was a huge gain of time for me as creating those supports from metal or wood would have been much more difficult.

If you are afraid of not being able to install universal parts like seats on your bike, don't worry, there is always a solution to achieve it without having to weld things. You just have to sit down and think of all the possibilities and be creative. I've seen many unfinished projects of cafe racer bikes for sale, most of them had a seat but that wasn't installed on the bike... for your project, you just have to be creative and never give up! there is always a way to achieve what you're looking for!

Step 8: Go for a Test Ride!

Are you ready for it??

This has to be the most exciting part for sure. Now that you've strip the bike down, renewed its components and installed new cafe racer or scrambler style part, it is time to test ride the beast!

Well, this part is pretty self explanatory haha. It is time to enjoy all the work you've done!

During the first ride, make sure to check every bolt every 10 minutes and make sure that everything you installed is secured and holding up well. This is very important for your safety! You need to make sure that the bike you've built is strong and reliable.

Needless to say that you always need to ride with a full riding gear including at least a helmet, gloves, a jacket and boots. I know how tempting it is sometimes to just go for 10 min ride with just a helmet but believe me, don't play with safety. I love motorcycles and I've rode some for about 10 years now, I also got into few crashes, and my riding gear always saved me from severe injuries.

I love riding my new bike and I have to say that riding a bike you've "built" has nothing to do with riding one you've bought ;)

I also had many people stopping by on the streets to compliment me on the bike and how it looked great and different which made me super happy :)

There is one final step in my build that I will do very soon: bring my fuel tank and seat to a car paint shop to have them repainted in a beautiful, deep red :)

So there you go folks, this is my Instructable on how to give a new life to an old motorcyle, and how to undertake a cafe racer project.

We've basically took an old bike that was very dusty, rusty and corroded, renewed everything and turn it into a brand new bike that do not fail to impress people on the streets :)

I hope this will be inspirational to some of you and make you take the plunge to make this cafe project you've been dreaming about.

And remember... if you like riding something you've bought, try riding something you've built... ;)


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