520 Upgrade Chain & Sprocket Set (Full Conversion Kit) – Hyosung GV125 Carby Aquila
Stop fighting your drivetrain and relax your screaming engine. This is the only store to offer a complete heavy-duty chain conversion built specifically for your V-twin cruiser, making a fresh Hyosung GV125 520 chain kit the single best way to clear up severe vibration and expand your high-speed cruising limits during a restoration project. #HyoRiders Exclusive!
- Lower Revs // Drop your engine stress dramatically! Cruise smoothly at 70mph around 7,000-8,000 RPM instead of screaming the motor out at maximum limits. 🏆 Less Revs Guaranteed
- Acceleration // Sharper, faster 0-70mph tracking! Moves away from under-geared factory limits to deliver a better torque pull in each gear. 🏆Faster Acceleration Guaranteed
- Box Contents // Everything included for the task! Arrives with 1x Gold 520 Link Chain, 1x Front Chromoly Sprocket, 1x Custom Rear High-Carbon Sprocket, 1x Genuine Locking Washer, and 4x Stainless Steel Carrier Fasteners.
- In Stock // Perfect if you are restoring your final drive system and rear wheel components to their former glory. #GoFASTER!
⚠️ CRITICAL EXCLUSIONS: This conversion assembly fits carb models only (2001-2017).
⌚ This is a special order, so allow a little extra time but see the estimated delivery times above ^
❌ It will strictly NOT fit the newer 2019 to 2026 EFi Bobbers or updated fuel-injected water-cooled layouts. (if you have a GV125-S EFi Bobber, click here instead)
Description
The Aquila engine is widely regarded as one of the best 125cc V-twins ever built, but original factory cost-cutting left the final drive assembly with a massive structural bottleneck: the skinny 428-pitch drivetrain. In its original form, your bike often feels severely under-geared—screaming at extreme limits up to 11,000 RPM just to battle against headwind and maintain a steady 60mph. This is the only store to offer this uprated 520 final drive conversion package. This professional-grade restoration overhaul replaces thin, high-maintenance factory links with heavy-duty 650cc-strength hardware, allowing your engine to breathe efficiently while clearing up intense frame vibration across your latest restoration project. 🏆This is a guaranteed upgrade for both longevity and speed
This isn’t a basic maintenance swap—it is an uprated engineering modification that has been thoroughly proven across our own active test donor bikes and backed up by a massive community of happy riders across the EU. Moving your transmission line up to a wide 520 pitch layout significantly expands the active roller surface area, distributing engine torque pulses evenly across the teeth to stop the constant chain stretch that ruins standard 428 kits. Real-world workbench testing confirms that this gearing shift alters the machine’s character completely. You can comfortably cruise at 30mph in fifth gear at an incredibly relaxed 2,500 RPM, hit an unbelievable 60mph in third gear (yes 3rd gear!), and unlock a true cruising top gear that safely carries heavy luggage and travel packs on long-distance journeys. #GoFaster!
💎 FINAL DRIVE HARDWARE HYOSUNG GV125 520 CHAIN KIT SPECIFICATIONS
| High-Carbon Steel SprocketsRear teeth cut from premium carbon metal matrices to resist hooking under touring loads. | Relaxed Motor CruisingAlters your gear ratios to lower high speed stress by thousands of RPM revolutions. |
| Premium Gold 520 chainHeavy-duty quad sealed plates finished in high gloss gold for maximum weather defense. | Full Conversion FastenersArrives loaded with a fresh sprocket lock washer, and four stainless carrier bolts. |
📜 Confirmed Fitment Guide
Hyosung Models: Rear carrier patterns and output shaft splines are verified strictly for the early v-twin cruiser setups listed below. See the diagram picture for rear hub layout lines.
- GV125 Aquila Carb Models: All years from 2001 to 2018.
- GV125 Mirage: Twin-carb models up to 2018.
🔧 Expert Installation & Gearing Notes
- Unbolt the Output Gear Spindle Safely: Always loosen the primary front sprocket nut on your workbench while your old original chain is still wrapped securely over the teeth. Keep the transmission clicked firmly in gear and step hard down on the rear brake pedal to safely stop the spindle shaft from rotating as you turn the hand tool.
- Lock Your Fold-Down Security Plate: Slide the fresh genuine factory lock washer onto the shaft splines before spinning your nut down. Once tightened up with a hand torque tool, use a flat chisel to bend the washer tab flush against the hex edge to physically lock the sprocket nut from loosening.
- Maintain Proper Alignment Lines: Ensure your rear axle adjustments are tracked perfectly square across both sides of the swingarm slots. Running a heavy duty conversion out of true will place an uneven side load on your sprockets, causing premature wear and tight links.
Additional information
| Weight | 3 kg |
|---|---|
| Dimensions | 30 × 30 × 4 cm |
8 reviews for 520 Upgrade Chain & Sprocket Set (Full Conversion Kit) – Hyosung GV125 Carby Aquila
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GARAGE PICKS // ADD TO BUILD
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NGK Uprated HT Coil Spark Plug Cap/Covers [x2] – Hyosung GTR GT GV (Various Models)
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NGK LASER Iridium Spark Plugs x2 – Hyosung GT/GV 125 250 650 Models
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Aftermarket Ignition Coil – Carby Hyosung GV125 GT125 GV250 GT125R GT250
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Sale!
Renthal Racing Front Engine Sprocket (for 520 Chain Kit) – Hyosung GT125R GT250R GT250
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Independent Shop supplying ride enhancements and quality spares with fast dispatch. Need assistance? Access our workshop guides, manuals, tutorials or drop by the forums for troubleshooting help.
David –
Just had this fitted big difference good deleviery aswel
Luke –
This was my major upgrade on my GV125. I can’t recommend this enough. Has greatly improved the performance, especially up hills.
Moustache Man –
Took out the 125 for a test spin and wow i am absolutely amazed.
I’m amazed at the rev range that it now provides, i can cruise at 2500rpm doing 30mph in gear 5, it actually hits 60mph in gear 3 which is crazy! I can cruise at 70mph at 8000-8500 revs, whilst beforehand I would only be able to just hit 70 at max revs, around 10500 to 11,000rpm. This means i can safely commute to work with the bike running at 7000rpm doing about 60 to 65mph which is fast and means the engine is under a lot less stress!!
Those gains are insane, however, the top speed is even more impressive. I was under the impression that the sprocket kit wouldn’t add power, but just shift the power band instead. Which is actually kinda correct. With the stock bike, I only managed to hit 70, barely 71mph.
With the new kit installed, I managed to hit 80mph today on a motorway. That’s insane! So fast for a 125cc!
Thanks for your amazing customer service, keeping me updated throughout my delivery
And thank you for the sprocket kit, it has sure made me happy this christmas. The bike is wonderful, and the acceleration too omg! It’s crazy! It gets to 0-60 in no time
Absolutely wonderful, would highly recommend this modification, so cheap and the chain is a lovely golden colour. Plus the chain seems a lot thicker than the stock one, so it’ll definitely take a couple thousand more miles than the stock one. I love it!
Joe Banks –
Upgraded the chain and sprockets on my GV 125 c, to the 520 chain, and what a difference it makes. From pulling away for the first time after fitting the differene was clear. Smoother and faster transference of power to the back wheel through the gears and fourth really does feel like fifth.
Really happy with this feels like a new bike. Cheers Marcel 😛
Joe Banks –
I have to agree to pretty much all Moustache Man has to say. Not had the chance to hit the motorway yet but was running up hill at 55 in fourth. Previously would have been struggling to sit on 50 uphill, I am bigger than average so it is to the bikes credit that it manages this :p.
Oliver –
After reading the reviews and speaking to Marcel I decided on getting this kit and I’m glad I did. Great quality parts and I have noticed a change in performance. I can now get 90mph out of it, which is crazy for a 125 cruser! It will comfortably ride at 70 all day and acceleration has improved to for safely getting away from idiot drivers haha! Would highly recommend
roy –
the 520 kit does actually work it changes your gear shifting altogether 5th is more like a 6th gear
i have had 70mph out of my aquila gv125 2008 reg and im around 18.5 stone.
of course i in my last review did not think much of the kit but i was in the wrong ( FOR THAT IM TRULY SORRY)
MY CARBS WERE AT FAULT
standard main jets are supposed to be both 87.5 ……………………….MINE WERE 82.5 BOTH
standard pilot jets are supposed to be both 15…………………………..MINE WERE 17.5 BOTH
so after doing the upgrade mentioned on here main jets front 90 and rear 92.5 MAIN JETS
and PILOT JETS 15 and 2 1/2 turns out with the mixture screws PLUS balancing the carbs .
fitting irridium plugs
fitting upgraded ngk plug caps found on here
my bike has gone from doing 55-60 at a push slowly………….TO A VERY FAST PICK UP AND 70MPH AND BELIEVE ME WHEN I SAY ITS FAST ENOUGH….
LASTS WORD GOES OUT TO MARCEL FOREST HE IS TRULY A GOOD GUY .
Balazs Wittman –
I just installed the kit and it’s amazing!
Feels smoother
And I gotta do more upgrades by roys review!
I feel like slowly making this bike better and better
Customer help is also 5*
You guys really helped me out with all! Thank you!