LC135 is 4-speed and 125Z have 6-speed: Why?
Have you ever wonder about this? Why is it the marvelous and lovable Yamaha LC135 only have 4-speed gear and Yamaha 125Z having additional 2 speed gear? Is Yamaha neglected the important aspect of speeds and thrills? Well, I have been thinking about this for a while and tried to find out why. Here is what I’ve found out…
The reason why Yamaha 125Z needed to have 6-speed gear is due to narrow powerband that is natural for 2-stroke engine. 2-stroke engine needs RPM more than 5000 (depends to the engine bore x stroke) to deliver its optimum torque, whereby 4-stroke engine can deliver the optimum torque from as low as 1500 RPM. So, because of this, 2-stroke engine needs to have a lot more gear than 4-stroke engine to make sure the torque can be spreads out all along the speed (km/h) starting from low speed to very high speed.
For example, LC135 can run on 4th gear as low as 20km/h and from there you can also speeds up to 140km/h without hesitation from the engine. Try this on your 125Z, and tell me how does it feels. It is an advantage of 4-stroke engine to have a wider powerband than the 2-stroke engine. One of the most known bike to have a very wide powerband 4-stroke engine is the Honda EX5. You can drive it slow and suddenly accelerate it without hesitation.
As you can see, having only 4-speed gear on LC135 is not a disadvantage, it is the nature of 4-stroke engine that have wide powerband. But, I think it is also not a wrong decision if Yamaha engineers decides to make LC135 being 6-speeder! More gear change, more fun!
For more info about 2-stroke engine, click here.