Engine hard to start

hi Josel.
Everything from the electrical system to the fuel system to the actual starter itself can be the problem. Finding the root cause of a hard starting engine can take some investigation. Ignoring a hard starting issue can further damage the vehicle, which will often result in a more expensive repair.

Car is hard to start Inspection Service A car that is hard to start can be a major inconvenience. While this is usually not a life threatening malfunction, it can make getting around much more difficult. There are a number of issues that will make a car hard to start. Everything from the electrical system to the fuel system to the actual starter itself can be the problem.
Finding the root cause of a hard starting engine can take some investigation. Ignoring a hard starting issue can further damage the vehicle, which will often result in a more expensive repair.
How this system works: In order to get an engine running, it must be turned at speed so that it starts to suck fuel and air into the cylinders, and then compress and ignite this fuel/air mixture.
The starter motor is an electric motor that turns the engine to get it started. The starter motor has a small pinion gear wheel that engages with a larger gear ring at the rim of the engine flywheel.
The starter motor draws the electric current it needs to run from the battery. The starter needs a heavy current and to avoid sparking a solenoid is used. The ignition switch operates the starter motor. When the ignition is turned on, current is fed to the solenoid and into the starter motor. Once the car engine starts and the key is released, the starter motor turns off.
Common reasons for this to happen:

• Bad Starter: Over time starter motors can wear out and start to malfunction. If this is the problem the starter will have to be replaced. If the car turns over, the problem is not the starter. If nothing happens when the key is turned the problem could be the starter, or if the car turns over very slowly and the dash lights dim while it is cranking, the starter could be the culprit.
• Bad Relay Wiring: The wiring between the battery and starter can become loose or broken which will prevent the starter motor from functioning. The wiring will need to be replaced or repaired.
• Low or Dead Battery: The starter motor needs voltage from the battery to operate. If the battery is low or failing it may not produce enough current for the starter motor to function. Charging or replacing the batter should resolve this problem.

It is also possible that the battery terminals have become corroded or loose. Cleaning and tightening the terminals and cables is recommended.

• Failing Solenoid: A failing solenoid is a common issue with the starter system and if the solenoid is going bad, the car will be difficult to start. The starter will need to be inspected to determine if the problem is the starter motor itself or the solenoid. A failing solenoid will need to be replaced.
• Failing Ignition Switch: Over time an ignition switch can start to fail and one of the most common symptoms is that the car is hard to start. If the ignition switch is hot to the touch this indicates an issue with the ignition switch wiring. A failing ignition switch will eventually stop working completely and will need to be replaced.
• Defective Fuel Pump: If the engine is not getting enough fuel, it will be hard, if not impossible to start. The fuel pump is responsible for pulling gas from the tank to the injectors and if it is not delivering enough fuel the car will be difficult to start and eventually will not start at all.
• Fouled Plugs: Spark plugs create the spark which allows the vehicle to burn fuel. Fouled plugs are one of the most common reasons for a hard starting engine. As electrodes wear down, the voltage required to jump the gap to ignite the fuel increases. This can lead to prolonged cranking before the engine will start.
• Clogged Fuel Filter: A fuel filter that is clogged can make a vehicle very difficult to start. The fuel filter screens out contaminants and can become clogged over time. This will prevent the injectors from getting enough fuel, making the car hard to start.
• Contaminated Fuel: Fuel that has too much alcohol or water in it will result in a car that is difficult and often impossible to start. Even if it does start, contaminated fuel can do serious damage to the engine. If contaminated fuel is suspected, have the vehicle inspected immediately.

What to expect: A top-rated mobile mechanic will come to your home or office to determine the source and cause of the hard to start issue, and will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done: The starter, battery, connecting wiring and other important components will be inspected by the mechanic. This may include the vehicle's fuel pump, fuel filter, spark plugs, ignition and more. It may be necessary for the mechanic to crank up the car to verify the problem and issue an accurate diagnosis.
How important is this service? If a car is hard to start, it's indicative of a major condition preventing normal operation and if left unattended it may lead to the car not starting at all. The vehicle should be inspected and repaired as soon as possible.

in what way is it hard to start does the engine turn over fast or slow, fast is low compression in the piston chambers slow can be the battery or the starter motor wearing out. ( starter motor has bushes to turn the motor these wear out and cannot turn the engine over fast enough to start.

When you turn off the motor & step on the brake
pedal 3 times, it should get hard

Then start the motor & engine vacuum should allow
the brake pedal to go almost to the floor

If you hear a hiss under the dash it (may) be bad

try turning the engine over by hand do it without the ignition on. see how hard it is to turn. turn it a few times then try to start with starter motor. if still will not turn check the starter motor is engaging. check wiring and make sure there is a good earth.

Testing the fuel pump electrical circuit should be done , voltage drop testing . Plus fuel pump pressure an flow testing , scan engine data parameters .
Testing Electric Fuel Pump Problems with Voltage Drop Test
048 Engine Hard to Start or No Start Scan Data for Starting Problems

Without hearing the sound it makes - it's kind of hard to diagnose.

The engine starting process consists of turning the key to start, the starter motor's rotor moving forward to engage the engine's flywheel, and then the starter motor 's "rotor" spinning until you move the key from "start" to "run". You can hear the starter motor spinning - but one usually can't hear the rotor moving forward to engage the flywheel. As a result, you hear the odd spinning sound - which is the starter rotor spinning. The engine never actually turns over because the rotor never engages the fly wheel. If this is the case, then it is very likely that your starter needs to be checked and / or replaced.

Good luck!

If the engine is turning over too slow, the engine will not start. Try either charging the battery first or attach a charger while starting. If it is still turning slow, the starter may be drawing too many amps and need to be replaced.

May be the problem is the hard turning of the motor. It may be caused by segments broken, bearings defective, oil problem etc.

Sounds like you have a problem with the timing chain and the valve timing is out meaning a valve is down when the piston at the top causing an interference. Take the spark plugs out and with the bike in a high gear and on the center stand see if the engine will turn over by hand by pulling the back wheel. Don't force it or you will bend a valve and damage the piston though it probably has happened already. You would need to open the engine up and see what is happening with the timing chain, valve timing etc and go from there.

Check fuel pressure, and regulator. A leaking regulator gives a warm engine more fuel [ it does not like it] a cold motor does. same as a flooded motor. Good luck