Product Description
PRIMA 15x12mm ROLLER WEIGHT TUNING KIT
2g–13g • 36 PIECES • YAMAHA / MINARELLI 50cc
Take the guesswork out of CVT tuning with the Prima 15x12mm Roller Weight Tuning Kit. This kit includes 36 color-coded rollers ranging from 2g to 13g, giving you an easy way to test different roller weights and dial in your scooter's acceleration, RPM, and overall CVT performance.
Perfect for Yamaha Jog, Zuma, Vino, C3 and many Minarelli-style 50cc engines.
PRODUCT DETAILS
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Brand: Prima
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Roller Size: 15mm × 12mm
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Weight Range: 2g–13g
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Quantity: 36 Rollers
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Weights Included: 2g, 3g, 4g, 5g, 6g, 7g, 8g, 9g, 10g, 11g, 12g & 13g
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Quantity Per Weight: 3 Rollers
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Color-Coded: Yes
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SKU / MPN: 1400-1083
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Made In: Taiwan
36-PIECE TUNING KIT
You receive 3 rollers of every weight from 2g through 13g:
2g • 3g • 4g • 5g • 6g • 7g • 8g • 9g • 10g • 11g • 12g • 13g
With three rollers of each weight, you can combine two different weights in a 6-roller variator to fine-tune your setup.
HALF-GRAM TUNING
Mix adjacent weights to achieve half-gram effective setups.
Example:
3 × 6g + 3 × 7g = 6.5g effective weight
3 × 7g + 3 × 8g = 7.5g effective weight
3 × 10g + 3 × 11g = 10.5g effective weight
This allows you to experiment with small changes before purchasing a complete set of your preferred roller weight.
WHAT ROLLER WEIGHT CHANGES
LIGHTER ROLLERS
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Higher engine RPM during acceleration
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Can provide quicker acceleration
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Helps modified engines stay higher in their powerband
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Useful for tuning performance exhaust, cylinder and other engine upgrades
HEAVIER ROLLERS
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Lower engine RPM at a given speed
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Variator shifts sooner
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Can provide smoother lower-RPM cruising
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Useful when an engine is revving higher than its ideal power range
IMPORTANT: Heavier rollers do not automatically mean more top speed, and lighter rollers do not automatically mean better performance. Correct roller weight depends on the engine setup, rider weight, terrain and desired RPM.
COMMON APPLICATIONS
Designed for variators using 15x12mm rollers, including many:
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Yamaha Jog 50
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Yamaha Zuma 50 2-Stroke
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Yamaha Vino 50 2-Stroke
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Yamaha C3 50
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Minarelli Horizontal Engines
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Minarelli Clone Engines
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1E40QMB / 1E40EQMB Engines
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1PE40QMB Engines
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1E41QMB Engines
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Various Chinese 50cc 2-Stroke Scooters
⚠ IMPORTANT FITMENT INFORMATION
PLEASE CHECK YOUR EXISTING ROLLER SIZE BEFORE ORDERING.
These rollers measure exactly:
15mm DIAMETER × 12mm WIDTH
Your variator MUST use 15x12mm rollers.
DO NOT purchase based only on scooter make, model or engine size. Variators may differ between models and may have been changed by a previous owner.
NOT FOR STANDARD 139QMB / GY6 50cc 4-STROKE VARIATORS
The common 139QMB GY6 50cc 4-stroke engine normally uses 16x13mm rollers.
These 15x12mm rollers are primarily intended for Yamaha / Minarelli-style 2-stroke applications and compatible variators.
Always compare the 15x12mm dimensions with your original rollers before ordering.
INSTALLATION / TUNING NOTE
When mixing two different roller weights, the weights must be alternated evenly around the variator to maintain proper balance.
Example:
6g – 7g – 6g – 7g – 6g – 7g
Never group three lighter rollers together and three heavier rollers together. An unbalanced variator can cause vibration, poor performance and component damage.
WHY USE A ROLLER TUNING KIT?
Changing CVT roller weights is one of the easiest ways to fine-tune a scooter's transmission.
This kit allows you to experiment with multiple combinations to find the setup that works best with your:
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Rider weight
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Engine modifications
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Exhaust system
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Cylinder / big-bore kit
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Variator
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Clutch setup
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Riding terrain
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Desired acceleration and RPM
Instead of buying multiple individual roller sets, you can test 2g through 13g with one convenient kit.
PRIMA PERFORMANCE PARTS
36 COLOR-CODED ROLLERS • 2g–13g • 15x12mm • MADE IN TAIWAN
SKU: 1400-1083
Distributed by GY6 STORE
