How do you know when to change gears?

how do you know when to change gears on a bike that has no rev meter?How do you know when to change gears?
If you listen to the engine, and feel the power it puts out, you find that above a certain speed you don't get more power, all you get is noise. You very quickly learn that the engine is 'happy' within a certain range of RPM.



Some types of motors have a very wide 'power band'. They don't really care what speed they're going. Often they have a speed limiter that will prevent them from being revved too high. These bikes don't have a tachometer because they don't need one! The Harley Davidson V-twin engine is like this.



The bikes that really do need a tachometer are sportbikes that make a lot of power at the top of their rev range. They have a very narrow powerband, so they really need a tach. If you ride one of these bikes, you notice it right away. You take off at 3000 rpm and the bike moves okay but as the engine speeds up, as the revs build, you feel more more power. Finally, around 8000 or 9000 rpm it's like something hit you from behind, the bike just suddenly jumps with power. But less 'sporty' engines don't have this characteristic.



But even with a sportbike like this, you quickly get used to the sound and feel of the engine so you know when to shift without looking at the tach.How do you know when to change gears?
Its all practice you will hear when you have to go to the next gear.
If you have a tachometer, keep on eye on it to make sure you don't red-line (over-rev) your engine. After you've ridden for awhile, you'll learn when to shift by the sound of your engine. When accelerating, make sure you shift soon enough to prevent over-revving and harming your engine. When decelerating, down-shift soon enough to prevent your engine from stalling. I can't be more specific about the RPM's at which to shift without knowing what type of motorcycle and size of engine you have.
It will tell you by buzzing the handlebars and vibrating.

Bikes have a very wide power band and so can shift at almost any point, If you think you should shift it's already well past the can stage.
I have been riding a 1968 BSA 441 SHOOTING STAR since 1972 ( not the the same one - this is my second) and you know what? I couldn't tell you - it's all automatic to me. And I never really thought about it until I saw your question. I just shift by the sound of the motor but there really are quite a few other variables that enter into it. Terrain - engine load - type of riding - road surface etc., etc.



It has become so second nature to me that I don't think about it - I just simply DO IT.



My best guess - when the motor starts to sound strained you may want to consider shifting. And if a piston goes through the gas tank - STOP.



And my son just got a 125cc dirt bike with no tachometer. I have never heard him over rev that either. I asked him how he knew when to shift and all he did was shrug his shoulders.



Truth - I have been riding motorcycles for over 40 years and cannot honestly remember the last time I looked at a tachometer. Just added useless weight on most bikes. And if there are no police around I rarely look at the speedo either.
Sound of the engine will change so you can hear it revving too high in one gear and sounds right when you up shift to the correct one. It works the same way going down in gears as well.