Riding a motorcycle in a crowded city such as Jakarta forces a rider to stop and accelerate frequently. If you drive a Yamaha NJMX, here’s how to increase its acceleration:
- Change the teeth number of the rear sprocket, from 38T to 40T.
You can feel the changing effect immediately. The “kick” is a lot stronger than using 39T. But the “breath” of each transmission decreases. It means the switching between transmissions happens more often because the engine reaches its “climax” fast. You’ll also experience a drop of top speed to around 80 km/hour.
- Change your standar coil to YZ125 coil.
The effect may not be as much as changing the rear sprocket, but it’s still significant. There are a lot dishonest sellers selling fake ones in Indonesia. So be careful. The size of YZ125 coil is bigger and longer than the standard. So the bracket won’t fit. You need to find a way to keep it in place.
- Use a platinum sparkplug.
I use NGK CPR8EAGP-9 sparkplug. NJMX has a high 10,9 : 1 machine compression. Based on what I’ve read, platinum sparkplug is suitable for a minimum 10:1 machine compression. The kick is mild, but it’s there.
The above modification touches the ignition part of your motorcycle by making the fire bigger. Even though bigger is not always good up to a certain point and may need more gas. You may also try changing the limiter with an aftermarket part. But personally I don’t want to go to that direction. Because it’s there for a reason.
There a few more things you should pay attention in order to achieve higher acceleration:
Certain type of tire could affect acceleration. Tires with harder compound are more speed friendly as well as smaller tires. But you need to consider your road condition, is it wet or dry, is it rocky or smooth. Using hard compound or small tires in a wrong road condition could lead to unwanted results or accidents. Flat tires will also decrease your acceleration. Because there will be more surface area contacting the road. So make sure to inflate your tires correctly.
- How clean is your chain?
A dirty chain will slow your bike. Since these dirt will add more friction between chain and gears. Use a chain cleaner to clean it, after that use a lubricant for chain to make it friction less. DO NOT use oil to lubricate your chain, since it’ll attract more dirt.
In the future I’m planning to change the drive chain to a thinner one by SSS to increase my motorcycle’s efficiency furthermore.
Time is important, isn’t it? So less time you spend in the road means more time to do something else.