03/04/2013
The Honda Grom, known affectionately as the 'king of the small bore', has captured the hearts of riders across the globe. This compact, fun-loving machine, with its agile handling and approachable size, offers an unparalleled canvas for customisation. Whether you're aiming for enhanced performance, a distinctive aesthetic, or improved rider comfort, the aftermarket world for the Honda Grom is vast and continuously expanding, allowing you to truly make this little powerhouse your own.
- Finding Your Aftermarket Grom Parts
- The Heart of the Beast: Understanding the Grom's Engine
- Boosting Performance: Exhaust Systems and Beyond
- Mastering the Ride: Suspension Upgrades
- Optimising Power Delivery: Sprocket Upgrades
- The Ultimate Power Play: Big Bore Kits
- Personalising Your Grom: Cosmetic and Safety Enhancements
- Frequently Asked Questions (FAQs)
- Conclusion
Finding Your Aftermarket Grom Parts
When it comes to sourcing aftermarket parts for your Honda Grom, the options are plentiful, though it's crucial to choose reputable suppliers. Many specialist motorcycle parts retailers, both brick-and-mortar and online, stock a wide array of components designed specifically for the Grom. Websites like ChapMoto.com, mentioned in the provided information, exemplify the kind of online resource where you can find parts engineered to fit perfectly and perform optimally on your Grom. These retailers often offer everything from engine internals to cosmetic enhancements, ensuring you can find the components you need to build your dream ride or simply replace worn-out parts.
It's always advisable to verify compatibility with your specific Grom model year, as minor changes can occur between production cycles. Furthermore, consider supporting businesses that specialise in small-bore motorcycles, as they often possess invaluable expertise and offer parts that have been tried and tested within the Grom community.
The Heart of the Beast: Understanding the Grom's Engine
At its core, the Honda Grom is powered by a robust 124cc four-stroke, air-cooled, single-cylinder engine. This compact power plant, first seen in the 2017 Honda Grom 125, delivers a modest 7 hp at 7,000 rpm and 11 Nm (approximately 8 lb-ft) of torque at 5,500 rpm. While these figures might seem humble, they contribute to the Grom's exceptional fuel economy and make it incredibly nimble for urban commuting and spirited rides. The bike's steel mono-backbone frame, coupled with a 31 mm inverted telescopic fork at the front and a steel box-section swingarm with a monoshock at the rear, provides a sturdy yet agile platform. Braking is handled by a 220 mm disc on the front, clamped by a dual-piston caliper, and a 190 mm disc on the rear, managed by a single-piston caliper.
Despite its factory specifications, the Grom's engine is ripe for modification, and many owners seek to unlock more power and responsiveness from this capable little motor. This desire for enhanced performance drives a significant portion of the aftermarket parts market.
Boosting Performance: Exhaust Systems and Beyond
One of the most popular and impactful upgrades for the Honda Grom is an aftermarket exhaust system. Not only do these systems typically offer a significant weight reduction over the stock unit, but they also improve exhaust flow, which can lead to modest gains in horsepower and torque. Furthermore, an aftermarket exhaust dramatically alters the sound profile of your Grom, giving it a much more aggressive and satisfying note.
For instance, Yoshimura, a renowned name in performance exhausts, offers systems like the R-77 mini, specifically designed for the Grom. These handcrafted stainless steel systems exemplify the quality and performance enhancements available. Beyond exhausts, other performance-oriented parts include high-flow air filters, upgraded fuel injectors, and performance camshafts, all designed to optimise the engine's breathing and combustion.
Mastering the Ride: Suspension Upgrades
While the stock suspension on the Honda Grom is adequate for casual riding, enthusiasts often find it can be significantly improved, especially when pushing the bike harder or if riding with a pillion. Upgrading the suspension can transform the Grom's handling, stability, and rider comfort.
Aftermarket suspension components include replacement front fork springs and cartridges, as well as high-performance rear shocks. These upgrades allow for finer tuning of damping and preload, better absorbing bumps and maintaining tyre contact with the road, even during aggressive cornering. The process typically involves disassembling parts of the bike, such as removing the lower fender from the swingarm or loosening the muffler to access bolts, to replace the stock components with superior aftermarket alternatives.
Optimising Power Delivery: Sprocket Upgrades
One of the most cost-effective and impactful performance upgrades for your Honda Grom is changing the front and/or rear sprockets. This modification allows you to fine-tune your bike's gear ratio to suit your specific riding style and desired performance characteristics. It's an easy-to-do upgrade that offers a significant 'bang for your buck'.
Sprocket Ratio Comparison:
| Sprocket Change | Effect on Acceleration | Effect on Top Speed | Typical Use Case |
|---|---|---|---|
| Smaller Front / Larger Rear | Significantly Increased | Slightly Decreased | Aggressive urban riding, stunt riding, track use, quicker launches |
| Larger Front / Smaller Rear | Slightly Decreased | Significantly Increased | Highway cruising, longer journeys, more relaxed riding |
| Balanced Combination | Moderately Increased | Maintained / Slightly Increased | All-rounder, good balance of acceleration and top speed |
By adjusting the sprocket sizes, you can prioritise razor-sharp acceleration for urban dodging and trick riding, or opt for a higher top speed to make highway journeys more comfortable and efficient. Many riders choose a combination that offers a good balance, providing improved acceleration without sacrificing too much top-end speed.
The Ultimate Power Play: Big Bore Kits
For those truly seeking to transform their Grom into a high-performance machine, a big bore kit is the ultimate upgrade. These kits significantly increase the engine's displacement, leading to substantial gains in horsepower and torque. A notable example is the DHM 186 kit, which is often described as an 'all-inclusive' package designed to convert your Honda Grom into a formidable big bore machine without the hassle of sourcing individual components.
Components of a Typical Big Bore Kit (e.g., DHM 186):
- 186cc Cylinder and Piston: The core of the upgrade, increasing engine displacement.
- Complete Oil Cooler Kit: Essential for managing the increased heat generated by the larger engine.
- OEM Honda PCX150 Fuel Injector: Provides the necessary fuel delivery for the increased displacement.
- DHM Reflash (or similar ECU tuning): Crucial for optimising fuel mapping and ignition timing for the new engine setup.
- Performance Camshaft (e.g., TB Camshaft or Decha HR Camshaft): Enhances valve lift and duration for improved airflow.
Performance Data Comparison (Stock vs. 186cc Big Bore Kit):
| Metric | Stock Honda Grom | 186cc Big Bore Kit | Gain |
|---|---|---|---|
| Horsepower (HP) | ~7 hp | ~16.5 hp | ~74% |
| Torque (Nm / lb-ft) | ~11 Nm (8 lb-ft) | ~14.5 lb-ft | ~67% |
| 0-50 mph Acceleration | ~9 seconds | ~5 seconds | ~44% faster |
These figures highlight the dramatic performance improvement a big bore kit can offer, transforming the Grom's acceleration and overall rideability. The ECU reflash is a critical component, requiring you to send your original ECU for modification or acquire a pre-flashed core unit. It ensures proper fuelling and timing for the new displacement and will adapt over the first 15-20 miles of riding. It's important that your stock narrowband O2 sensor remains installed and plugged in for the ECU to learn effectively.
While not strictly required, an upgraded intake and exhaust system are highly recommended to maximise the benefits of a big bore kit. Furthermore, given the increased heat generated, an oil temperature gauge (from brands like OPMID or Koso) is strongly advised, especially if you plan on regular highway trips, to ensure the engine does not overheat. Although these kits are designed to be bolt-on, reliable power upgrades, professional installation is recommended if you are not experienced with engine work.
Personalising Your Grom: Cosmetic and Safety Enhancements
Beyond performance, the aftermarket offers a vast array of parts to customise your Grom's appearance and enhance its safety. Cosmetic upgrades allow you to make your bike truly unique and reflect your personal style.
- Exterior Parts: This category includes a wide variety of components such as aftermarket mirrors, LED lighting kits, and licence plate relocation kits. These simple changes can drastically alter the visual appeal of your Grom.
- Stretched Look: For those seeking a distinctive, low-slung aesthetic, a Honda Grom Swingarm Stretch Kit with Lowering Link Package is a popular choice, providing that custom 'stretched' appearance.
Safety should always be paramount, and several aftermarket parts can help protect both you and your bike in the event of an unforeseen incident:
- Folding Levers: Folding brake and clutch levers are designed to pivot away upon impact, significantly reducing the chance of them breaking in a minor fall.
- Frame Sliders: These are strategic points of contact that protrude from the frame, designed to absorb impact and keep the main components of the bike off the ground during a slide, minimising damage.
- Folding Kick-start: Similar to folding levers, a folding kick-start can prevent damage to the lever itself and the engine casing in a spill.
These safety components are crucial investments that can save you significant repair costs and keep your Grom on the road.
Frequently Asked Questions (FAQs)
Where can I buy aftermarket Honda Grom parts?
You can purchase aftermarket Honda Grom parts from a variety of sources, including reputable online retailers specialising in motorcycle parts, dedicated small-bore motorcycle shops, and even some general motorcycle dealerships. Websites like ChapMoto.com are examples of places that offer a wide selection of parts designed for the Grom. It's always best to check for compatibility with your specific model year.
What type of engine does a Honda Grom use?
The Honda Grom is typically powered by a 124cc (or similar low displacement) four-stroke, air-cooled, single-cylinder engine. For example, the 2017 Honda Grom 125 featured an engine that delivered 7 hp at 7,000 rpm and 11 Nm (8 lb-ft) torque at 5,500 rpm. This engine is known for its reliability and fuel efficiency.
What's new with the Honda Grom in terms of aftermarket options?
The aftermarket for the Honda Grom is constantly evolving. Manufacturers regularly release new products, such as new exhaust systems (like the Yoshimura R-77 mini systems), advanced suspension components, and even comprehensive big bore kits. Given the Grom's popularity, new items are frequently developed to meet rider demand for enhanced performance, aesthetics, and functionality. It's always worth checking with specialist retailers for the latest additions.
How can I upgrade the suspension on my Honda Grom?
Upgrading your Honda Grom's suspension typically involves replacing stock components with aftermarket parts like stiffer front fork springs, upgraded fork cartridges, and higher-performance rear shocks. The process can involve disassembling parts of the bike, such as removing the lower fender from the swingarm or loosening the muffler to access suspension bolts. While some basic steps can be followed at home, professional installation is recommended for optimal performance and safety, especially if you're not experienced with suspension work.
How do I upgrade my Honda Grom sprocket?
Upgrading your Honda Grom's sprocket involves replacing the front and/or rear sprockets to alter the gear ratio. A smaller front sprocket or larger rear sprocket will increase acceleration at the expense of top speed, while the opposite will increase top speed but reduce acceleration. This is a relatively easy and cost-effective upgrade that allows you to tailor your Grom's performance to your riding style. It typically involves removing the chain and replacing the sprockets before re-tensioning the chain.
What is a TBParts Grom kit?
A TBParts Grom kit, often found as part of a larger package like the DHM 186 kit, refers to a comprehensive big bore package designed to significantly increase the Honda Grom's engine displacement and power output. These kits typically include a larger cylinder and piston (e.g., 186cc), an oil cooler, a performance camshaft, and often require an upgraded fuel injector and an ECU reflash for proper fuelling and timing. They are designed to provide a substantial boost in horsepower and torque, transforming the Grom into a much more powerful machine.
Conclusion
The Honda Grom, with its playful nature and robust engineering, offers an incredible foundation for customisation. From subtle cosmetic tweaks to dramatic engine overhauls, the aftermarket provides a wealth of options to tailor your Grom to your exact specifications. Whether you're chasing more horsepower, sharper handling, or simply a unique look that turns heads, investing in quality aftermarket parts allows you to unlock the full potential of your 'king of the small bore' and enjoy a truly personalised riding experience. Remember to always prioritise safety and consider professional installation for more complex modifications to ensure your Grom performs as intended.
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