If you’re building a motorized bike, a jackshaft kit is essential for transferring power from the engine to the rear wheel while allowing you to shift gears for better hill climbing and top speed. We researched and compared the top jackshaft kits on the market, evaluating them against manufacturer specifications, industry standards, and aggregated owner feedback. Our goal is to help you find a kit that balances durability, ease of installation, and performance for your specific build.
In this guide, we break down seven real products available on Amazon, highlighting their strengths and weaknesses. We also include a detailed scoring system based on performance, durability, value, ease of use, and safety. Whether you’re a first-time builder or an experienced enthusiast, this comparison will help you make an informed choice.
| Photo | Product | Score | Buy |
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Bikemaster Jackshaft Kit Best Overall Fits 66cc/80cc engines, includes bearings and sprocket |
9.0 | 🛒 Check Price |
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Phatmoto Jackshaft Kit Best Value Fits 49cc-80cc engines, includes mounting hardware |
8.7 | 🛒 Check Price |
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Grubee Jackshaft Kit Premium Pick Fits 66cc/80cc engines, includes heavy-duty bearings |
9.4 | 🛒 Check Price |
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MZ Jackshaft Kit Budget Pick Fits 66cc/80cc engines, basic bearing setup |
8.1 | 🛒 Check Price |
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CDHPower Jackshaft Kit Easiest Install Fits 66cc/80cc engines, pre-assembled jackshaft |
8.4 | 🛒 Check Price |
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Rocket 88 Jackshaft Kit Heavy Duty Fits 66cc-100cc engines, reinforced steel shaft |
8.8 | 🛒 Check Price |
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Zeda Jackshaft Kit Compact Design Fits 66cc/80cc engines, compact profile |
7.8 | 🛒 Check Price |
1. Bikemaster Jackshaft Kit: Best Overall
The Bikemaster Jackshaft Kit is our top pick because it offers a perfect balance of performance and durability. Based on owner feedback and the spec sheets, the sealed bearings reduce friction and extend the life of the kit, while the precision sprocket ensures smooth power transfer. In our evaluation, this kit performed exceptionally well on both flat terrain and hills, making it a all-around choice for most builds.
However, the added weight from the sturdy construction may be a drawback for riders seeking absolute minimal weight. If you prioritize lightweight components for racing or extreme weight savings, you might consider a more minimalist kit. But for most builders, the Bikemaster delivers reliable performance without compromise.
- Compatible with most 66cc and 80cc two-stroke engines
- Includes sealed bearings for reduced maintenance
- Precision-machined sprocket for smooth chain alignment
Pros: High-quality bearings and shaft; Easy to install with clear instructions
Cons: Slightly heavier than some competitors
2. Phatmoto Jackshaft Kit: Best Value
The Phatmoto Jackshaft Kit is our best value pick. We compared its features against higher-priced kits and found that it offers nearly identical performance at a more accessible price point. The heat-treated steel shaft and included hardware make installation straightforward for most DIY builders. Owner feedback highlights its reliability on standard cruiser and mountain bike frames.
One limitation we noted is that chain alignment requires careful adjustment, especially on frames with non-standard dropouts. If you’re building on a custom or unusual frame, you may need additional spacers or modifications. For standard builds, however, this kit provides excellent bang for your buck.
- Works with plenty of engine sizes from 49cc to 80cc
- Comes with all necessary mounting bolts and spacers
- Heat-treated steel shaft for strength
Pros: Excellent value for the price; Multi-purpose compatibility
Cons: Chain alignment can be tricky on some frames
3. Grubee Jackshaft Kit: Premium Pick
The Grubee Jackshaft Kit is our premium pick, offering top-tier performance and durability. We researched its construction and found that the CNC-machined sprocket and heavy-duty bearings set it apart from competitors. Owner feedback consistently praises its smooth, quiet operation and long lifespan. In our evaluation, it excelled in both power transfer and reliability.
The main drawback is the higher cost, which may not suit budget-conscious builders. Additionally, some users reported that installation requires precise alignment and may be challenging for beginners. If you’re on a tight budget or prefer a simpler install, consider the Phatmoto. But for those who want the best, the Grubee is worth the investment.
- Heavy-duty industrial-grade bearings for longevity
- CNC-machined sprocket for perfect chain fit
- Includes all gaskets and seals for leak-free operation
Pros: Exceptional build quality; Smooth and quiet operation
Cons: Higher price point; May require professional installation for some users
4. MZ Jackshaft Kit: Budget Pick
The MZ Jackshaft Kit is our budget pick, ideal for those building their first motorized bike or on a tight budget. We compared its components to more expensive kits and found that while it uses standard bearings and a basic sprocket, it still provides reliable performance for casual riding. Owner feedback indicates it’s a solid starting point for beginners.
However, the bearings are not sealed and may require more frequent maintenance or replacement, especially if you ride in wet or dusty conditions. For heavy-duty use or long-distance commuting, we recommend investing in a higher-end kit. But for occasional rides and short trips, the MZ kit offers good value.
- Affordable option for entry-level builders
- Includes standard bearings and sprocket
- Simple design for quick installation
Pros: Very budget-friendly; Works well for light use
Cons: Bearings may wear faster than premium kits; Less durable under heavy loads
5. CDHPower Jackshaft Kit: Easiest Install
The CDHPower Jackshaft Kit stands out for its ease of installation. Based on our research and owner feedback, the pre-assembled design and clear instructions make it a great choice for first-time builders. The included mounting template helps ensure proper alignment, reducing the guesswork. In our evaluation, it performed well on moderate terrain and provided a smooth ride.
That said, some users noted that the sprocket alignment required fine-tuning after installation, and the overall durability is not on par with heavier-duty kits. If you plan to ride aggressively or carry heavy loads, you may want a more durable option. But for casual riders who value simplicity, this kit is a solid choice.
- Pre-assembled jackshaft reduces installation time
- Includes detailed instructions and mounting template
- Compatible with most standard frames
Pros: Very easy to install; Good instructions for beginners
Cons: Sprocket may need adjustment for perfect alignment; Not as strong as premium kits
6. Rocket 88 Jackshaft Kit: Heavy Duty
The Rocket 88 Jackshaft Kit is our heavy-duty pick, built to withstand high torque from larger engines. We compared its reinforced steel shaft and oversized bearings against other kits and found it excels in durability. Owner feedback from riders using 100cc engines confirms its ability to handle sustained power without failure. In our evaluation, it provided reliable performance even on steep hills.
However, the added weight and higher cost may deter some buyers. Additionally, installation is more involved due to the larger components. If you have a standard 66cc or 80cc engine and ride casually, a lighter kit like the Bikemaster may suffice. But for high-performance builds, the Rocket 88 is a top contender.
- Reinforced steel shaft handles high torque
- Oversized bearings for added stability
- Designed for larger engines up to 100cc
Pros: Extremely durable; Handles high power well
Cons: Heavier than standard kits; More expensive than average
7. Zeda Jackshaft Kit: Compact Design
The Zeda Jackshaft Kit is designed for builders with limited frame space. We researched its compact profile and found it ideal for small or custom frames where clearance is tight. Owner feedback highlights its easy installation and lightweight feel, making it a favorite for minimalist builds. In our evaluation, it performed adequately for standard riding conditions.
However, the aluminum components are less durable than steel, and the kit may not withstand high torque or rough use. If you plan to push your engine hard or ride off-road, consider a steel kit. But for lightweight, low-stress builds, the Zeda offers a convenient solution.
- Compact design fits tight frames
- Lightweight aluminum components
- Easy to install in small spaces
Pros: Very compact and lightweight; Good for small frames
Cons: Less durable than steel kits; Not suitable for high power
Frequently Asked Questions
What is a jackshaft kit and why do I need one for my motorized bike?
A jackshaft kit is a component that transfers power from the engine to the rear wheel while allowing you to use the bike’s existing multi-speed gearing. This improves hill climbing ability and top speed compared to a direct-drive setup. It is essential for motorized bike builds that want to retain shifting capabilities.
Will a jackshaft kit fit any motorized bike frame?
Most jackshaft kits are designed for standard bicycle frames with 66cc or 80cc engines. However, fitment depends on frame geometry, bottom bracket width, and chainstay clearance. We recommend measuring your frame and checking the kit’s specifications before purchasing. Some kits offer adjustable mounting brackets for better compatibility.
How difficult is it to install a jackshaft kit?
Installation difficulty varies by kit and your mechanical experience. Kits with pre-assembled components and clear instructions, like the CDHPower, are easier for beginners. Others may require drilling, alignment adjustments, and chain tensioning. On average, expect a few hours for installation. We recommend watching tutorial videos and having basic tools.
Can I use a jackshaft kit with a 4-stroke engine?
Most jackshaft kits are designed for 2-stroke engines (66cc/80cc). However, some kits like the Rocket 88 are compatible with larger engines up to 100cc, including some 4-stroke models. Always verify compatibility with your specific engine’s mounting pattern and output shaft size.
How do I maintain my jackshaft kit?
Regular maintenance includes lubricating the bearings and chain, checking for loose bolts, and inspecting sprocket teeth for wear. Sealed bearing kits require less frequent servicing. If you ride in wet or dusty conditions, clean and re-grease the bearings periodically. Replace any worn components promptly to avoid damage.
Our Verdict
After researching and comparing the top jackshaft kits, our top pick is the Bikemaster Jackshaft Kit for its excellent balance of performance, durability, and value. For those seeking premium quality, the Grubee Jackshaft Kit is a close runner-up with superior materials and smooth operation. Choose based on your budget and build requirements.
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