These Polini counterpressure springs increase pressure by 15%, making them ideal for light tuning. When the level of tune increases, so too should the strength of the springs. Variator must be calibrated if springs are changed. Original Spring Loading: 45/31.5mm/kg Polini Spring Loading: 45/37mm/kg Spring Thickness: 4.1mm Spring Length: 115mm Inside Diameter: 53mm Number of Turns: 5 MBK Flame XC125 Xie 10- Doodo 125 00- 5MF Doodo 150 00- 5PR Flame XC125 X 04-07 5ML Skyliner 125 01-02 5NR Skyliner 125 03-06 5XL Skyliner 125 07-09 5D8 Skyliner 125 98-01 5DS Skyliner 150 00- 5NS Thunder 125 01-03 5HT Thunder 150 00- 5HT Waap 125 06-07 Waap 125i 08- SE421 X-Over 125 ie 4T Yamaha Zuma / BWs 125 ie 4T 10- SE55 Cygnus XC125 X 04-07 SE081 Cygnus XC125 Xie 08- SE411 Majesty 125 01-02 SE061 Majesty 125 03-06 SE066 Majesty 125 07-09 SE068 Majesty 125 98-01 SE021 Majesty 125 Limited Ed. SE066 Majesty 150 00- SG051 Maxster 125 01-03 SE051 Maxster 150 01- SG061 Teos 125 00-03 SE041 Teos 150 01- SG071 Vity 125 06-07 Vity 125i 08- SE421