CVT Setup & Roller Tuning Guide

⚙️ CVT Setup & Roller Tuning Guide – Rev Cycle

This guide explains how to tune your CVT system for acceleration, top speed, and optimal performance on Honda Dio (AF27/AF28) and similar scooters.

📦 CVT System Basics:

Your CVT (Continuously Variable Transmission) includes:

  • Variator (front pulley)
  • Roller weights
  • Drive belt
  • Clutch shoes
  • Clutch bell
  • Torque driver (rear pulley)
  • Clutch springs + center spring

Each part affects how your bike launches, shifts, and tops out.

⚖️ Roller Weight Guide:

Roller weights control how fast your variator shifts. Lighter = more revs, Heavier = faster shift.

Roller Weight Result Notes
4–5g High RPM, fast takeoff Better for short tracks/city
6–7g Balanced acceleration + top end Good all-around choice
8–9g Lower RPM, more top speed Ideal for big bore + longer runs

💡 Tip: Mix 3 light + 3 heavy rollers (in alternating pattern) to test combinations.

🌀 Clutch Springs:

These control when the clutch grabs. Higher RPM springs = faster launch, but too high can delay engagement.

Spring Rate Engagement RPM Use Case
1000 RPM Early engagement Daily riding, smoother
1500 RPM Medium engagement Mixed setups
2000 RPM Late engagement Race builds, high rev only

🪝 Center Spring (Torque Spring):

This spring pushes back on the rear pulley. Stiffer = more tension = more aggressive downshifting.

  • Soft (stock): smoother shifting, less tension
  • Medium (1000–1500 RPM): balanced for 70–90cc
  • Hard (1500–2000 RPM): needed for 100cc+ or stiff belts

🔧 Setup Examples:

🏁 80cc Daily Street:

  • Rollers: 6g
  • Springs: 1500 RPM clutch + 1000 RPM center
  • Belt: 15.5x669

🔥 90cc Performance:

  • Rollers: 7g or mix 6/7g
  • Springs: 2000 RPM clutch + 1500 RPM center
  • Belt: reinforced Kevlar or Bando belt

🚀 120km/h Top Speed Build:

  • Rollers: 8–9g
  • Springs: 2000 RPM clutch + 1500–2000 center
  • Gear ratio: 16/42 or taller

📏 Belt Size:

Most Dio setups use 15.5x669 or 16x669. Measure your current belt and check for wear or glazing.

📉 Common Mistakes:

  • ❌ Rollers too light = high revs but no speed
  • ❌ Springs too stiff = slow launch or laggy feel
  • ❌ Worn belt = slips under load

💬 Still Need Help?

Message us at revcyclehelp@gmail.com with your engine setup and goal (daily, wheelie, top speed, etc.) and we’ll guide you.

⚠️ Disclaimer: Always test tuning changes in a safe area. Use proper tools and torque specs. Performance tuning is at your own risk.