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Description
Naraku 139QMB / GY6 50cc Super Transmission Kit w/ Clutch, Belt, Variator KitNaraku 139QMB GY6 50cc Super Transmission Kit w Clutch, Belt, Variator Kit Restore lost top speed, eliminate off the line bogging, and completely refresh your drivetrain with the Naraku Super Transmission Kit. Engineered specifically for 50cc and 49cc GY6 50 139QMB 4 stroke engines, this all in one CVT tuning package replaces your entire worn factory transmission setup. By matching a high performance variator, precision balanced clutch assembly, heavy
Naraku 139QMB / GY6 50cc Super Transmission Kit w/ Clutch, Belt, Variator Kit
Restore lost top speed, eliminate off-the-line bogging, and completely refresh your drivetrain with the Naraku Super Transmission Kit. Engineered specifically for 50cc and 49cc GY6 50 / 139QMB 4-stroke engines, this all-in-one CVT tuning package replaces your entire worn factory transmission setup. By matching a high-performance variator, precision-balanced clutch assembly, heavy-duty clutch bell, and a calibrated drive belt, Naraku delivers seamless linear shifting, crisp throttle response, and maximum power transfer to the rear wheel.
What's Included in the Box
- Performance Variator & Drive Face: Optimized roller ramp angles maximize belt travel for improved acceleration and high-end speed. Includes a 26-spline drive face.
- Pre-Assembled Clutch & Torque Spring Base: Features durable, high-friction clutch shoes and an anti-slip torque spring base to ensure positive engagement under load.
- Heavy-Duty Clutch Bell: Precision-vented steel clutch drum designed for rapid heat dissipation, preventing thermal glazing and clutch chatter.
- Premium V-Belt: High-tensile drive belt selected for optimal dimensional stability and minimal stretching under high thermal strain.
GY6 50cc engines come in three distinct case lengths. Use the drop-down menu to select the correct kit configuration for your scooter platform:
| Belt Option | Engine Case Profile | Common Vehicle Applications & Notes |
|---|---|---|
| 669mm Kit | Short Case (10" Rear Wheel) | Fits standard short-case GY6 50cc scooters running small 10-inch rear wheels (e.g., ATM50-A1, VIP, and classic city scooters). |
| 729mm Kit | Long Case (12" or 13" Rear Wheel) | Fits standard long-case GY6 50cc scooters running larger 12 or 13-inch wheels. Always verify your case measurement matches a long configuration. |
| 788mm Kit | Extra-Long Case (Fat-Tire / Custom) | Engineered for extended-case variants, most notably found on the Icebear Maddog 50cc and similar Honda Ruckus clone platforms. |
Technical Specifications
- Engine Compatibility: GY6 50cc / 49cc 139QMB / QMB139 4-Stroke
- Roller Weight Size: 16mm x 13mm (6g weights included)
- Variator Outer Diameter: 88mm
- Drive Face: 26 Splines | 13mm Inner Diameter | 113.7mm Outer Diameter
- Clutch Drum: 22 Splines | 11.10mm Inner Diameter
- Sliding Torque Spring Base: 118mm Outer Diameter
- Manufacturer: Naraku (Germany)
Tuning Note: The included 6g roller weights provide an excellent balanced starting point for stock or lightly modified 50cc engines. If you have an 80cc Big Bore Kit installed, experiment with heavier or lighter weights to match your modified torque curve.
Installation Tip: Clean the crankshaft splines carefully before installing new components. Never use an impact gun to tighten the variator or clutch nuts without a holding tool — improper torque can strip crank threads or crush components.
Questions about parts & compatibility? Visit the contact page. - HB SCOOTERS PARTS - Professional Scooter Dealership in Southern California Since 2008
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.3 ★★★★★
Based on 23 reviews
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Product Reviews
★★★★★ 5
I’m A PT AND USING THEM IN MY CLINIC. PLS READ HONEST AND THOROUGH REVIEW.
Style: 15 Pound, Pair
I have been a PHYSICAL THERAPIST FOR 30 YEARS and I BOUGHT THESE FOR MY CLINIC. THESE WEIGHTS ARE COVERED IN A GRIPPING MATERIAL, NEOPRENE, MAKING IT COMFORTABLE and EASIER TO USE, ALLOWS YOU TO NOT LOSE YOUR GRIP, and IT IMPROVES THE SAFETY OF THE USER. I WILL BE BUYING THE 12&20 lb sets! THE VALUE FOR YOUR MONEY IS WONDERFUL!! AMAZON BASICS REALLY CAME THROUGH. It DID NOT INCLUDE AN INSTRUCTION GUIDE TO USE WEIGHTS SAFELY AND EFFECTIVELY. STELLAR FORM IS ALWAYS ESSENTIAL.
MY WEIGHTS WENT UP TO 10 POUNDS, SO I DEFINITELY NEEDED ADDITIONAL WEIGHTS for those who can SAFELY TRANSITION . I MAINLY WORK AS A MANUAL THERAPIST …USING ONLY MY HANDS, AND MY BRAIN. TO DIAGNOSE AND TREAT ACCORDINGLY.
(**ANYONE WHO HAS BEEN TO PT KNOWS THIS KIND OF ONE ON ONE TREATMENT IS UNHEARD OF**)
I IMPLEMENTED MYOFASCIAL RELEASE, TRIGGER POINT THERAPY, DEEP TISSUE MASSAGE, AND APPROPRIATE STRETCHING AND EXERCISE . ONCE PATIENTS WERE ABLE, I INITIATED THERAPEUTIC EXERCISE. I WAS GETTING SO MANY REFERRALS THAT I MOVED FROM MY SMALL SPACE AND GOT A LARGER SPACE THAT LOOKS LIKE A TYPICAL PT CLINIC. I STILL EMPLOY ONE ON ONE TREATMENT, NO JUGGLING SEVERAL PATIENTS IN AN HOUR. I HAVE HIRED HELP TO ASSIST PATIENTS WITH EXERCISE AND STRETCHING. I PURCHASED TWO ADDITIONAL SETS ITHE SET IT I DID TO FIRST CHECK THEM OUT. I ADORE THESE AND HAVE SINCE ORDERED OTHER SETS. I LOVE TO WORKOUT AND I NEEDED TO USE THESE WEIGHTS MYSELF!! THERE ARE ALSO PATIENTS OF MINE WHO WILL PROGRESS TO THESE AS WELL. I AM SUPER IMPRESSED WITH THESE WEIGHTS AND CANNOT WAIT TO RECEIVE MY TWO OTHER SETS!! YOU WILL NOT BE DISAPPOINTED.
EVEN IF YOU SWEAT, YOU ARE STILL ABLE TO HOLD ONTO THESE WEIGHTS COMFORTABLY AND SAFELY. SAFETY IS KEY, ALWAYS. I WAS EXTREMELY DELIGHTED THAT THEY ARE SOLD AS A SET BECAUSE MANY ARE SOLD SEPARATELY. THEY FIT PROPERLY ON A UNIVERSAL WEIGHT STAND, SO THEY ARE VERY EASY TO STORE. I CANT WAIT TO GET MY OTHER SETS! IT IS REALLY SAFE AND COMFORTABLE TO USE THESE WEIGHTS.
THEY DID NOT GIVE OFF AN ODD ODOR, which is A HUGE PLUS because SOME OTHER BRANDS SMELL HEAVILY OF PLASTIC OR A CHEMICAL TYPE ODOR. THERE WAS NO ODOR AT ALL. THIS IS A HUGE PLUS. I AM COMFORTABLE SAYING THAT THESE WEIGHTS WILL LAST A LONG TIME BECAUSE OF HOW WELL THEY ARE MADE. YOU CANNOT BEAT THE PRICE EITHER!!
THESE ARE ABSOLUTELY APPROPRIATE FOR PROFESSIONAL USE, AND, THEY ARE MEANT FOR PERSONAL USE AS WELL. SOMETIMES YOU JUST CANNOT GET TO THE GYM SO THIS IS WHERE THEY ARE KEY. HAND WEIGHTS HAVE THE ABILITY TO EXERCISE EACH MUSCLE OF THE TORSO AND ARMS. THERE ARE SOME EXCELLENT WEIGHT CHARTS OUT THERE TO SHOW YOU HOW TO DO THAT. IF YOU ARE GOING TO PHYSICAL THERAPY, THEN YOUR THERAPIST CAN INSTRUCT YOU AND KEEP YOU IN GOOD FORM. YOU COULD POSSIBLY HURT YOURSELF IF YOU WORKOUT INCORRECTLY. AS FAR AS THE LOWER EXTREMITIES, YOU CAN DO GROSS MOTOR EXERCISES BY HOLDING THESE WEIGHTS TO GET YOUR LEG MUSCLES BY DOING SQUATS, WALKING LUNGES, TOE RAISES, AND MORE. I DONT BELIEVE THAT MANY PEOPLE REALIZE JUST HOW MUCH YOU CAN DO FULL BODY EXERCISES WITH JUST TWO HAND WEIGHTS.
IN CONCLUSION , THESE ARE EXCELLENT WEIGHTS THAT I WOULD RECOMMEND TO MY PATIENTS OR FRIENDS. THIS IS A HIGH QUALITY PRODUCT THAT WONT BREAK YOUR PIGGY BANK. I HIGHLY RECOMMEND VERY HIGHLY!. BUY WITHOUT RESERVATION!! A+++
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Reviewed in the United States on March 23, 2025
★★★★★ 4
Perfect size and weight with compact size
Style: Rack with 3 Pairs (3, 5, and 8 Pound)
I purchased the Amazon Basics Neoprene Dumbbell Hand Weights specifically for Pilates, and they’ve been a great addition to my routine. The size and weight are perfect for controlled movements, helping with muscle toning without feeling too bulky or awkward.
The neoprene coating gives them a comfortable, non-slip grip, which is especially important during longer sessions or when your hands get a little sweaty. They feel secure and easy to hold through a full workout.
I also like the shape—they don’t roll around on the floor, which makes transitions between exercises smoother and less frustrating. They’re compact enough to store easily but still feel durable and well-made.
Overall, these are a simple, affordable, and effective option for Pilates or light strength training. I’d definitely recommend them for anyone looking to add a little resistance to their workouts without overcomplicating things.
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Reviewed in the United States on April 20, 2026
★★★★★ 5
Well made , gym quality
Style: 10 Pound, Pair
Color is nice and bright . The weights grips are good they do not slip . Prices reflect quality
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Reviewed in the United States on May 29, 2026
★★★★★ 5
Good purchase
Style: 3 Pound, Pair
These are just the right weight for me to start gaining muscle back in my arms, after a large weight loss. They are of good quality, they are covered in a nice rubber like coating that is soft to the touch. They are small enough that i can take them with me when I travel. My dog has got hold of them a couple times and played with them, and they held up just fine without any damage.
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Reviewed in the United States on April 28, 2026
★★★★★ 5
Solid, grippy, and they don’t roll away!
Style: 10 Pound, Pair
I bought these because I’m finally trying to build a consistent home workout routine and didn't want to drop a fortune on name-brand weights. I’ve been using this 10lb pair for about a month now for everything from overhead presses to lunges, and honestly, they’re exactly what I was looking for.
The Pros:
• That Neoprene Grip: The coating is fantastic. Even when my hands get pretty sweaty halfway through a workout, I don’t feel like I’m going to drop them. It’s a much "softer" feel than cold metal or hard plastic.
• The Hex Shape: This is a small detail that makes a huge difference. Since the ends are hexagonal, they don't roll across the floor when I set them down between sets. They also stay put if I’m using them for "renegade rows" or floor work.
• Compact Size: They aren’t bulky. I can easily shove them under my bed or in the corner of the closet when I’m done.
• No Weird Odor: I was worried they might smell like a tire factory (which happens with some rubber-coated weights), but these had almost no scent right out of the box.
The Cons:
• Handle Diameter: The handles are a little on the thicker side. I have medium-sized hands and it’s fine, but if you have very small hands, they might feel a bit chunky to wrap your fingers all the way around.
• Color Scuffs: The navy blue looks great, but if you clank them together or drop them on concrete, the coating can scuff or show dust pretty easily.
The Verdict:
If you just need a reliable set of weights for HIIT, Pilates, or general strength training, these are a no-brainer. You're basically getting gym-quality equipment for a fraction of the price. I’ll probably be back for the 15lb set in a few months!
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Reviewed in the United States on January 27, 2026
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