Malossi contrast spring yellow (reinforced) – clean variator tuning for Minarelli 100 2-stroke

With the reinforced yellow Malossi contrast spring, you get an important setup part for your variator. Especially for Minarelli 100 2-stroke engines (e.g., Yamaha Aerox 100, MBK Booster 100 or Aprilia Scarabeo 100), the correct spring tension determines how smoothly the belt works and how smooth the acceleration is.

The art of tuning lies in the correct combination of contrast spring, variator weights, and clutch springs. If your V-belt slips, you must definitely choose a harder contrast spring. However: a spring that is too hard can also have a negative effect on power output – so fine-tuning counts here instead of "maximum hardness".

If you are stuck with your setup, feel free to check an online community – almost every conceivable combination has been tested and documented there by now.

Advantages & Features

• Reinforced version (yellow) for variator tuning
• Helps with slipping V-belt (in conjunction with correct setup)
• Important component for a harmonious interplay of contrast spring, variator weights, and clutch springs
• Proven Malossi quality for reliable function

Technical Details

• Type: contrast spring / contrast spring / variator spring
• Version: yellow, reinforced
• Engine: Minarelli 100 2-stroke

Compatibility (Vehicles)

Fits many vehicles with Minarelli 100 2-stroke, such as Yamaha Aerox 100, MBK Booster 100 and Aprilia Scarabeo 100 – but also many other models:

• Aprilia: Scarabeo 100 2-stroke
• Aprilia: Scarabeo 50 2-stroke (1999–2009)
• Benelli: Naked 100 2-stroke
• Benelli: K2 100 2-stroke
• Benelli: K2 50 AC (air-cooled)
• Benelli: K2 50 LC (water-cooled)
• Italjet: Milenium 100 2-stroke
• MBK: Booster 100 2-stroke
• MBK: Booster 50 12 inch (2004)
• MBK: Booster Spirit 50
• MBK: Booster Track 50
• MBK: Booster Rocket 50
• MBK: Ovetto 50 (up to model year 07) (2007)
• MBK: Nitro 50 (1999)
• MBK: Nitro 100 2-stroke
• MBK: Nitro Naked 50 (2013)
• MBK: Ovettto 100 2-stroke
• MBK: Nitro 50 Cat (2003)
• MBK: Booster 50 NG (1999)
• Yamaha: BWS 100 2-stroke
• Yamaha: Neos 100 2-stroke
• Yamaha: Aerox 100 2-stroke

OEM Numbers (for comparison)

• 2911388.Y0
• 2911388Y0

Note: OEM numbers are for comparison purposes only.

Why Malossi?

Malossi has stood for well-thought-out tuning and adjustment components for years. With the right spring combination, you can make the variator work noticeably more cleanly – especially for setups around Yamaha Aerox 100 and Co.