The fuel-injected scooter may not start due to several reasons. It could be a problem with the fuel system, such as a clogged fuel filter or a faulty fuel pump. Additionally, issues with the spark plugs, battery, or ignition system could also prevent the scooter from starting. It is important to troubleshoot each of these components to determine the exact cause of the starting issue. **

A fuel-injected sports exhaust is an exhaust system designed to work in conjunction with a fuel-injected engine, typically found in high-performance sports cars. This type of exhaust is engineered to optimize the flow of exhaust gases, allowing for better engine performance and increased power output. It often features larger diameter piping, high-flow mufflers, and sometimes even electronic valves to control the exhaust flow. Overall, a fuel-injected sports exhaust is designed to enhance the performance and sound of a sports car's engine. **

Fuel-injected scooters are not necessarily bad, but there are a few potential drawbacks. One downside is that they tend to be more expensive than carbureted scooters, both in terms of initial cost and maintenance. Additionally, fuel-injected scooters may require more specialized knowledge and tools for repairs, which can make servicing them more challenging. Finally, some riders prefer the simplicity and ease of maintenance that comes with a carbureted scooter. **

There could be several reasons why a 4-stroke fuel-injected scooter won't start. It could be due to a faulty spark plug, clogged fuel filter, low battery, or a problem with the fuel injection system. It is important to check these components and ensure they are functioning properly to diagnose and fix the issue. If the problem persists, it may be best to consult a professional mechanic for further assistance. **

The Speedfight 4 fuel-injected model can be derestricted by modifying the ECU (Engine Control Unit) to remove the electronic speed limiter. This can be done by reprogramming the ECU with a new software or by installing a aftermarket performance ECU. Additionally, the exhaust system can be upgraded to a less restrictive one to improve the flow of exhaust gases and increase performance. It is important to note that derestricting a vehicle may void the warranty and can also have legal implications, so it is important to consider these factors before making any modifications. **

More fuel is injected during a cold start because the engine needs a richer fuel mixture to ignite and run smoothly in colder temperatures. Cold air is denser and contains more oxygen, so the engine actually needs more fuel to maintain the proper air-to-fuel ratio for combustion. Injecting more fuel helps to compensate for the reduced vaporization of fuel in the colder air, ensuring that the engine starts and runs efficiently in cold conditions. Therefore, less air is not injected during a cold start because the engine needs a higher fuel-to-air ratio to operate effectively in colder temperatures. **

The Speedfight 4 2-stroke fuel-injected scooter was first introduced in 2015 as a 2016 model year. This means that the model year of the Speedfight 4 2-stroke fuel-injected scooter is 2016. **

A sports air filter can have a noticeable effect on a 125cc fuel-injected motorcycle by improving airflow to the engine, which can result in a slight increase in horsepower and throttle response. However, the impact may not be significant enough to drastically change the performance of the motorcycle. It is important to note that the effect of a sports air filter can vary depending on the specific make and model of the motorcycle, as well as other modifications that have been made to the bike. **