Performance is something we all strive for in our bikes, we all love to accelerate our bikes, it is by far one of the most important factors that play crucial role in our buying decision. Given a chance majority of us would like to increase the performance of our stock condition motorcycles. There are two approaches we can consider while increasing the performance of our bikes, first is the Pro-approach, where our mission to increase the performance is to fulfill our professional goal, this includes serious modification in engine as well as other vital components of the bike. Professional riders and professional stunters can take this approach. However we are not discussing these serious modification here neither we recommend to do these modifications at home on your own or by any amateur mechanic.
We are going to guide you through the second approach, which is relatively a conservative but effective one. Here we will discus few easy to implement scientific techniques to increase power and performance of your 4-stroke machines be it a commuter or an already sportbike.
As we all know that there are mainly three steps involved in any internal combustion engine(2-stroke or 4-stroke) i.e Intake, Combustion and Exhaust. We will try to explain you the techniques of increasing the bikes' performance through these steps.
Intake:Intake involves input of Air and Fuel to the engine for efficient burning of the mixture of two in the next step i.e Combustion. Now intake of air to the engine normally done via Air filter.
Air Filter:
An air filter not only filters the intake air but it also governs the amount of air delivers to the engine. There are High Free Flow Air Filters available in the market from many reputed brands, K&N air filters are one of those brands which can be used for obstruction-less clean air to the engine.
Re-Jetting:
The next important element of "Intake" is Fuel, it is not to mention that a good quality of fuel always perform better. As we all know that it is the mixture of Air and Fuel that burns at the combustion chamber of the engine in the upcoming next step, there is a fixed ratio of both air and fuel in this mixture for the optimum combustion to take place, now as we have increased the effective volume of the air by putting the High Free Flow Air Filter, we also have to increase the amount of the fuel in the same ratio to match the figure.
To increase the volume of the fuel as well we need to increase the size of the "fuel Jet" present in the carburetor, the fuel-jet is a little nozzel present in the carburetor containing tiny holes through which fuel passes and get mixed with air in form of fine mist. Replacing the standard size jet by the increased size fuel-jet is called "Re-Jetting". It is important to do re-jetting with proper size fuel-jet after replacing the ordinary air filter with High free flow air filter to get the desirable results, performing either of the activities by avoiding the other one is not recommended, it needs to be done simultaneously.
Note: For 4-stroke bikes with Fuel Injection System, which are devoid of carburetor instead of re-jetting the ECU needs to be re-mapped.
Combustion:The combustion is the process where the mixture of Air and fuel gets burnt with the help of "Spark Plug". The efficient the spark produced by the spark plug the better the combustion takes place. For an efficient spark producing spark plug you need "Iridium spark plugs" which not only last longer but produces consistent high voltage spark.
High voltage Cord:
The high voltage producing iridium spark plugs also need high voltage resisting spark plug cord to support the current drawn from the coil to the iridium spark plug. You should always replace the spark plug with the set of iridium spark plug and the coil with the cord. If you use the high voltage drawing iridium spark plug without the corresponding matching cord it may melt down the regular standard spark plug cord.
Exhaust:After efficient combustion takes place successfully the residual gasses must also be expelled out efficiently. The Exhaust pipe which is also commonly known as "Silencer" is not actually meant for suppressing the noise only, it plays the vital role in managing the back pressure created by the hot gasses coming out from the combustion chamber, which in-turn is very important for overall performance of the bike.
Free Flow Exhaust:
The free flow exhaust system is as important as the above mentioned points to enhance the power and performance of the 4-stroke motorcycle. There are many after market exhaust pipes available, always use the exhaust system which fits your bike perfectly and never use loose fitting exhaust as leakage of the exhaust gasses may hamper the utility of your exhaust system.
Sprocket Gearing:This is probably the only modification that can be done standalone in the bike to increase the pick up or acceleration. Leave apart this all the above discussed modifications are to be done simultaneously to get the maximum benefit out of it.
By altering the gearing of the bike you can achieve either maximum top speed or the maximum acceleration. The final drive train of a bike generally is chain type and to transmit the power from the engine this chain runs through a set of "chain sprocket" the smaller front chain sprocket with relatively lesser teeth and the bigger rear sprocket with more teeth. By either reducing one tooth from the front sprocket or increasing one or two teeth in the rear chain sprocket we can achieve greater acceleration and by reverting the process we can achieve greater top speed.
Note: Replacing the rear chain sprocket with either less or more teeth are relatively easier and safer.
This way you not only can achieve the maximum augment in the power output of your bike but also get maximum performance at the minimum cost and modification involved. Here I left the major modification involved for the professional causes, which I will discuss in my later article, stay tuned for more on other aspects of biking and share you mind with your fellow bikers and motorcycle aficionados through your comments.
Ride hard & Ride safe!!
By: Farhan Kashif