CJM
01-17-2012, 01:56 PM
I know many of you wonder the answer to this, I mean I know why but not everyone does.
Sparks racing explains it better than I ever can:
Why does my 4-stroke bog or even sometime die when I snap the throttle open in neutral from a low idle?
The manifold pressure is very low at idle, which is essentially how hard the motor is sucking air and fuel from the carburetor. The FCR is a very efficient carburetor and can flow a lot of air. When you snap the throttle open very quickly, there is a brief lag before the accelerator pump gets enough fuel to mix with all of the air you just gave the motor. Essentially the motor goes super lean for an instant. That is the bog that you are feeling. When you get the rpm’s up a little and then snap the throttle, the motor will respond properly. If it does not hesitate during normal riding, then you are fine. You will notice this even more so on thumb throttles than twist throttle because of how quickly the thumb throttle can open a carburetor compared to the twist throttle.
Sparks racing explains it better than I ever can:
Why does my 4-stroke bog or even sometime die when I snap the throttle open in neutral from a low idle?
The manifold pressure is very low at idle, which is essentially how hard the motor is sucking air and fuel from the carburetor. The FCR is a very efficient carburetor and can flow a lot of air. When you snap the throttle open very quickly, there is a brief lag before the accelerator pump gets enough fuel to mix with all of the air you just gave the motor. Essentially the motor goes super lean for an instant. That is the bog that you are feeling. When you get the rpm’s up a little and then snap the throttle, the motor will respond properly. If it does not hesitate during normal riding, then you are fine. You will notice this even more so on thumb throttles than twist throttle because of how quickly the thumb throttle can open a carburetor compared to the twist throttle.