According to Wikipedia A custom motorcycle is a motorcycle with stylistic and/or structural changes to the 'standard' mass-produced machine offered by major manufacturers.
This is a simple way of looking at the broad spectrum of what motorcycle customization really is.
I am not going to be talking about the craziness that goes on in the back yard garages of bikers out in the US who literally have a fully functional machine shop in their garages since my experience is based in India (But I do so wish I was in the US for Customization right now!!!!!!!!!!!!!!).
At most when a person utters the words customization or modification here in India with regards to motorcycles the things that come to mind would be changing or altering the exhausts to make the bike sound louder, a K&N air filter to maybe give the bike a better sound (and not for the fact that it enables the bike to breath better), change the handlebar to either drag bars or small apes depending to the person who rides it and maybe , Just maybe a change in colour which would sometimes just mean pasting stickers on top of factory paint so that it looks different from the tens of thousands of bikes on the streets of India.
It’s hard to pin point any one thing that defines motorcycle customization since for each person who owns a motorcycle they each have particular needs. Sure what I said earlier about the views of most people in India on the subject would be considered as a very infinitesimally small part of what customization actually is. I quite frankly don’t think anyone on the face of this planet can actually give a full holistic definition of customization but what I can tell you are some facets that are considered while customizing a motorcycle.
No two people are alike physically except in the case of a set of identical twins or triplets but even then there will be some very subtle differences between them.
Let us take for example two people were to have bought the same bike each but had different build and body structure, then each of the bikes would need to be modified to fit the build of each of the owners.
If the person is tall and heavier built the bike would need to have s taller seat, suspension would need to be changed to compensate for the weight as well as the ground clearance and overall height of the bike to make it suit the tall heavy built rider.
If the rider is short and light the suspension would need to be adjusted or changed to accommodate the person to be comfortable while sitting on the bike or riding while allowing them to be able to place their feet firmly and securely on the ground.
Modifying the motorcycle to the shape and size of the rider and owner is what is known as customizing for fit.
People buy motorcycles for many reasons. It could be part of their mid life crisis, commuting requirements, status symbol, cross country touring, etc.
Each of these scenarios would require the bike needing to function in different relevant ways.
For an example of the motorcycle is to be meant for cross country touring like riding out from Bangalore to Delhi then there would be quite a few things that would need to be done for the bike.
If the person will be riding through the night then the bike would need good bright and powerful lighting.
Since they would be riding for hours on end they would need to be in the saddle for a long time which would mean the appropriate type of seat that will allow them to do so.
If the person is taking a pillion along then a pillion seat if the bike does not already come equipped with it and also a pillion backrest so that the pillion is comfortable at all times (let’s face it, if the person sitting behind you is miserable through the journey then you are going to be miserable through the journey, so make them comfortable.)
In terms of safety if anything were to cause the rider to lose control it is always a good idea to have protection items that would save the crucial parts of the motorcycle from unnecessary damage be it frame sliders, engine guards, bash plates, etc.
For long journeys the bike would need an addition of luggage which would help the rider and pillion take a good amount of the essentials for as many days as they require when they are on the ride.
These are only a few things that can be done on a motorcycle in terms of functionality.
A lot of people would want to be able to use as much power as the engine can muster on a long ride in order to get from one point to the other quickly and efficiently so that would be where a good set of free flow exhausts with the addition of a good air intake and a fuel management system would come in as the first step to unlock the restricted power that the motorcycle comes with. A good side effect of this change is that you get the motorcycle to sound much better and more noticeable than it was initially which is always a good thing.
Another step in which a person can improve performance of the motorcycle is by changing internal components like cam shafts, bores and piston kits, etc to increase the overall performance of the motorcycle even more than what could be achieved by external modification.
This is a very broad topic where a person can change the look of their bikes in subtle ways like hand grips, foot pegs, different seat covers and leathers, engine casing trims, wheels, custom colours for the body panels and body parts. Going either for a dark and majority black theme or getting as much chrome on the bike as possible or maybe even a combination and good balance of both chrome and black.
Custom paints can be anything the person wants. From solid single colours, to dual tones, to fine or bold pin stripe work, even simple graphics and designs that has significance to the persons existence on this planet to absolutely over the top elaborate and crazy historical scenes that the rider identifies with in their lives.
So to get back to the question, “What is motorcycle Customization?”
Well, it’s all of the above and so much more which I really don’t know if we would be able to fully and properly define in this lifetime.