One of the best things about the Honda Grom is that it’s easily customizable, and its long history means there are a lot of different parts on the market available for doing so.
In fact, I’ve found that a number of aftermarket parts can improve the Grom’s performance far beyond its already impressive 10 horsepower and 62-mph max speed.
These are the best Honda Grom performance parts and my favorite models for each.
Big Bore Kit
The Grom definitely has a powerful engine for its size, getting close to 10 horsepower. Nevertheless, there’s only so much speed you can get out of 125cc.
If you want to bump up the speed from the Grom’s 62-mph max, a great place to start is by increasing the size of the engine with a big bore kit.
Basically, these increase the size of the piston bores, thereby increasing engine displacement and power.
Some kits also modify the engine in other ways. For instance, some increase the Grom’s engine from four valves to two.
This is a simple but effective kit that increases the Grom's engine size from 125cc to 170cc. More than anything, it gives you a lot more torque and acceleration—and better wheelies.
Combined with the Koso 170cc cylinder kit, use this kit to double your Grom's valves. Including a forged piston, it greatly enhances the power and torque of your Grom so you can get better speed and acceleration on the road.
An aftermarket exhaust system will also improve your Grom’s performance because it improves airflow into the engine. As extra bonuses, it can also improve fuel efficiency and sound much sexier and more powerful.
Like exhausts, upgrading your air intake will greatly improve airflow for your Grom.
This means the fuel combusts more efficiently, releasing more energy and giving your bike more power, torque and acceleration.
If you’re modifying your exhaust, you should definitely upgrade the intake as well for maximum performance enhancement.
Getting aftermarket suspension products with better travel than the factory parts, both of which have four inches of travel, makes riding the Honda Grom a lot more comfortable, especially if you’ve increased its torque with other upgrades.
Not only that, it also improves general performance because it makes the weight transfer more efficient during acceleration. This means it’s more responsive and just plain faster.
As a gas shock, this rear suspension greatly improves balance and absorbs impacts. That means you'll be a lot more comfortable, especially if you're on the heavier side.
Ohlins is a popular brand when it comes to suspension due to the high quality, durability, and smooth shock absorption that's well worth the top-shelf price.
In my opinion, a fuel controller is the most overlooked way to improve your motorcycle’s performance—and one of the best. While upgraded intakes and exhausts increase airflow, a fuel controller helps the fuel injectors increase the amount of fuel in the engine. The two together mean more power.
Increased airflow on its own will still give you more power, but it will do so by burning the fuel at higher temperatures, which can be bad for the engine in the long run.
Fuel controller plus exhaust and intake is the ideal combo, which is why many upgrade kits come with them.
Your Grom’s clutch might be a basic part, but it’s also a good one to upgrade to give your bike more performance.
A more responsive clutch means better acceleration since you can more accurately shift through gears as you speed up.
More importantly, stock clutches often wear out quickly and begin to slip, decreasing performance. An aftermarket clutch will be more durable and keep performance consistent over a longer period.
Get Koso quality and performance at a great value. The high-friction discs reduce slipping and improve responsiveness.
Made with Kevlar, this high-quality clutch kit will keep you shifting gears smoothly year after year.
You should upgrade your Grom’s rearset for one big reason: you can lean the bike over much farther, so you can take turns sharper and faster.
Already a high-performance minibike, you can make your Grom an even faster, more powerful and better handling machine by installing aftermarket performance parts.
Specifically, consider upgrading your Grom with a new:
- Big Bore Kit
- Fuel Controller
With high-quality models of these parts, you can create a custom Grom that’s even more fun to ride.