Learn Moto

How we became motorcycle mechanics.

Literature for homework

I personally have spent a lot of time looking for resources on motorcycle mechanics, but my problem had always been that it is such a large topic, so that dummy newbies like me hardly find their directions on where to start. I only now realize that it takes patience until you have actually gathered enough knowledge to be able to distuingish useful resources, and start puzzling this huge science together.

I have recently been introduced to these books and firmly recommend them as homework: Motorcycle Basics Techbook and Motorcycle Electrical Manual.

Also I find that old mechanic books may help more then a lot. A simple reason for that is that old motorcycles were more user friendly  in terms of maintance. They were more simple, easier to understand. These old handbooks might also have beautiful hand-drawn technical images, which you will never find for new motorcycle models due to their ridiculous complexity.

The Heart – Part II.

Thoughts on being a cardiac surgeon

There was some word about the types of engines in the last post, underlining 2T and 4T. It is hard to emphesize it well enough, how important it really is to do some homework, and develop a good overstanding of these engine types. Mechanics is not all about the material. The immense amount of theories, calculations, thought and experience behind these creatures is what actually makes them work. There is a number of helpful and reliable sources out there to help you learn about them. On wikipedia or on youtube too. Even about how they are made like this video.  It is really recommended for anyone into mechanics to spend some time going through these if you are not familiar enough with concepts like cranckhaft rotation degrees or spark advance.  It is a great rewarding feeling to actually know how it works. But the details that are often missed however some of these are the real eye-openers.

If I tell you that engines are precisely engineered, that might not be a big surprise. But If I tell you that dealing with them desires measurements made in the a range of 0,001-0,01 millimeters, whether it is a condition check, setting up a diagnose or actually amendment, now that is something surprising.  Follow this simple logic: if an engine does 6 thousand rotations per minute, that means one hundred per second. It’s even difficult to imagine the piston travelling up and down at this rate, a hundred up and a hundred down per second in a four stroke engine. But the fact that it is pushed by a series of combustions makes it even more ridiculous. Like the other fact, that the difference in size between the piston and the cylinder, in terms of diameter is only 0,02 milimeter. And this precise thinking is absolutely needed for all those astronomical number of combustions that they go through in their lifetimes.

However, they are robust. If love, rightousness and passion are attributes to describe a heart, an engine would be attributed by friction, heat, pressure.  There is no other way around it, they are built to be solid, so they last for at least a trip or two. This comes with a lot of engineering in the backround. The relatively light structure, materials used for each screw, sealings or coatings are precisely chosen and developed.

We are ought to respect that, and develop an approach that helps us to regard these pieces as something precious, fragile.

The Heart – Part I.

The heart
(In general)


What really makes me think of engines as the heart of motorcycles is the fact that after starting, and completing their first revolution they just keep on going. Of course, they need fuel, air and sparks, but still the moment of starting is just so much like the midwife patting on the back of a newborn baby’s. It cries, and so the system flows.

As a mechanic it is inevitable to have a good overstanding of the engine itself.  It’s the part of the system that creates all the power the bike uses, and it is also probably the most precisely engineered part of it.

First, let’s see the different types of internal combustion engines used in nowaday’s motorcycles. 2 Stroke Engines (or 2T) are becoming outdated but there are still many on the roads around the globe, and they have a large number of fans. They complete their working cycle in two strokes,  oppesed to 4 Stroke Engines (4T) where each phase takes a stroke.  4T engines are the most common out there  (especially in cars, only these are used recently and allowed  due to enviromantal and sound restrictions).  Their build-up and workinkg mechanism is similar, and they complete the same 4 phases throughout their work cycles:  Intake, Compression, Power, Exhaust. Only the 2T completes two at a time.

Wikipedia gives a great description with images and animations about both the 2T, and the 4T engine types.

For both of them there are several kinds of setups on motorcycles, which differ by the number and the position of the cylinders, and their valve controlling systems. For example, a boxxer is when the cylinders are in pair, and positioned against each other, so their pistons move in the opposite directions, or a V-twin is where the two cylinders are positioned forming  a “V” shape.  All engines are mainly attributed by the size of the cylinder, measured in cubic centimetres (or cc’s), which basically refer to the amount of fuel and air mixture that they burn in each power phase. Their RPM (rotation per minute) capacity is not less important either, which tells us how many revolutions per minute they are up to. It’s easy to understand that their power is mainly a function of these two properties: how fast they spin, and how strong the spinning force is.  2T enines compared to 4T ones with the same CC and RPM are more powerful because of their more concentrated working mechanism:  they complete the cycle in only 2 strokes or 1 revolution .

These engines power the most bikes out there but naturally there are oddities.  Armies tend to use and develop diesel engines, or as an other odd example,  some run with those strange Wankel engines.  Also there are more and more electric vehicles. However, on this blog we will focus on those usual, real-world examples that are the most frequent and roll out there in daily use.

To be continued…

What is a motorcycle?

Apart from being a commuter or sport instrument. A piece of art. It’s even more. Let’s see from a technical point of view.
The internal combustion engines generally work with an efficiency up to  30-40%. The rest, 60-70 percent of the energy that an engine produces is not translated into motion but simply into heat. So the motorbike is a machine that produces heat. Therefore it is also a machine designed to cool itself !
It gets all the power by burning liquid into gas. And that has to flow through its system, so, it is also a flow technology based design.
But it’s even more than that. It has two wheels, yet when running it is stable, and maintains a straight line of motion. It’s a gyroscope ! Given not only by the mass of the wheels, but even more importantly the crank shaft’s rotation. This effect actually plays a huge role in defining the riding experience (for example, 4 cylinders has a wider and heavier crankshaft then v2).
The story doesn’t end here. It has lights, it communicates, ignites, and does even more that requires electricity. So it is an electric device too!
And… It won’t go anywhere without a rider. A good rider perhaps. But that’s another story. Now we can see, that it is in fact a very complex organism, that requires a fine balance from many aspects to operate smoothly and sustainably.

7 questions

 (To the authors of the blog)

– What was your first experience with motorbikes that got you into it?

Pep: One of my friends took me for a ride on his large cc scooter in Paris. High speed, on the motorway. I literally had to hold on to my pants. When he asked me, before the ride, if it was OK that we take the scooter, I thought he meant one of those “pushscooters”.

Lev: I was about 13-14 years old, when my brother asked my family to come to the backyard to have a look at his new purchase. It was a dusty old classic bike: a black Danuvia 125. That moment, for me, was stunning.

It brought up a memory I had long forgotten, from times when I was so small that I didn’t even try to reach for door handles, or get in a bathtub alone. That time we had a moped, a huge and beautiful wonder of the garage. It was my father’s, and out of order for years. The shape of it was so  extreme and complicated that I had no chance climbing on it. I just span the front wheel that was slightly off-ground, redirected the headlight that was out of order too, moved the metal arms that are near to the part I knew I should place my feet on. I could do this for hours. When my brother came to the garage and saw me playing there, he put me on the moped. We “rode” it together sometimes, but he also often let me do it alone: I was making the noise of the engine out loud with my mouth, and steering the handlebar. With one hand, because my arms were too short to grab both ends while turning. I also imitated bumpy roads, moving it like a clumsy rocking horse.

It disappeared later and neither me or my brother was doing anything about motorbikes at all, until he appeared with the Danuvia. This old memory was brought up then, merging into the image of the beautiful new bike standing in our backyard. At that very moment I irreversibly got into it…

– What motivates you in riding?

Pep: Freedom at the most. The aesthetics of the mechanical complexity.And of course, a drop of adrenalin and nice curves. Yes, Nice Curves !

Lev: Mainly the motorbike itself, as an object. When riding i am always smiling inside, even when i focus on an intense traffic situation. Im not a big fun of the adrenalin tho…

– What motivates you to learn mechanics?

Pep: Bikes appear in my mind as living organisms, so it is daring and challenging to heal them or make them better. I’m also into electric vehicles.

Lev: Putting old, or simply half-dead bikes and parts together, and make them work again. It can be quite emotional.

– What was the most difficult mechanic fix you did on a bike so far?

Pep: Filling gas, haha. Ok, let’s say something like adjusting a carburator or replacing an igniter.

Lev: Starting my Kymco with dead choke is almost like a daily mechanic fix. I have replaced brake shoes in drum brakes, I think that was the most difficult so far.

– Self-built dream custom bike?

Pep: Kaneda’s bike from AKIRA with a little more Italian feel to it. A ducati 749 turned into a tourer. Or a BMW gs1200 ‘ratified’.

Lev: A scrambler, using up mostly low budget but quality used parts, except the ones that are crucial for safety and comfort, like suspension, and forks: those would be high-end, no matter what.

– Spaghetti, sushi or steak?

Pep: Sushi but only when it comes to eating. Damn I prefer Italian bikes even if they fall apart. Like we all do, sooner or later.

Lev: Half steak – half sushi.

– What is your favourite part of the motorbike?

Pep: Its heart, the engine of course. But I appreciate those things like handlebar, wheels or chain. You wouldn’t get far without them. That’s the beauty of it.

Lev: I would say the engine in general, but it depends. On a Honda Pacific Coast it’s the body, on a TW 125  it’s the combination of the rear wheel, saddle and fuel tank.

The Danuvia two years later. Due to the momentum of excessive enthusiasm we painted it stylish black and white instead of authentic black.

The Danuvia two years later. Due to the momentum of excessive enthusiasm we painted it stylish black and white instead of authentic black.

The Goal

Our goal is to gain a general good overstanding of motorcycle mechanics . To be able to fix bikes, diagnose errors, and do some customization. And perhaps in the future to create new designs, but basic motorcycle mechanics is the first step.

We are starting as young padavans in a school dedicated for motorcycle mechanics in september, and the course will run for a year. So by 2014 summer, we should be arriving to a turning point, regarding our first step. This is the goal. And of course to give a good account  of how it goes, on this blog.

Heroism, without much glow…

A brief tale of how it all started. In the role of the protagonist, a tiny little taiwanese scooter that actually brought us, the two authors of this blog, Lev and Dr.P closer together as friends, and inspired our future dreams for diving deeper into the guts of gasoline creatures. This red beast is called Kymco Heroism to this very day, and has a relatively fat chassis on a 50cc heart.

When I got to know this speed deamon for the first time, it was covered with the sort of angelic dust telling you that nobody used it for… let’s say a while. At that time I knew nothing of scooters and motorbikes other then they were fun to ride as hell, espacially on the parisian motorways as a passenger. However I was in craving need for a scooter as a busy man, so when Lev agreed to lend it to me in return for making it work properly and having it go under basic mechanic maintance, I felt like a fairly good deal had been made. Obviously, I did not know what we were facing.

Everyone knows those stories about impossible missions, breaking the vehicle down to parts on a monthly basis and trying to figure out where the problem is. You might as well know the feeling when it takes you from home to work and back, but it is just not as it should be. Yes, talking about torque, acceleration and the feel of it.  But the story of how this minor frustration turns into vital interest for two friends over the years is the point I am trying to tell here, and in the future posts to follow on this topic. This bike deserves to be an Icon in our story of learning mechanics, and I swear we will make it’s name ‘Heroism’ well  deserved soon enough.

To Be Continued…


Kymco Heroism 50 – artwork by Lev