Yamaha Zuma Mineralli
Mineralli Engine Upgrade
The Mineralli engine is use in two stroke Yamaha Zuma (Jog 50) scooters as well as Adley Moto, Mosquito, CPI, Keeway, Yamati, Starda, Jonway. The chinese brands like Keeway, Yamati and Jonway copied the Jog 90 engine so they have 10mm wrist pin bearings and 16mm tapers on crank shaft for variator leaving Yamaha with 10mm wrist pin and 13mm taper.
The stock carbs on the Yamaha Zuma are 15mm which is small compared to the 17.5mm on the chinese scooters using the 40QMB engines. Stock clutches are 150mm as well as clutch bell. The Chinese 40QMB as well as CPI and Keeway are what most think and are called 112mm or 110mm. Now 107mm clutches and clutch bells well do very well on both Yamaha and Chinese 40QMB which for my self is a super strong engine nothing wrong here. The Chinese two stroke slams out of the box as well as CPI does.
A very good combo of parts for both types is 70cc cylinder kit, 107mm clutch and bell. 4gram weights, 2000RPM torque spring as well as racing variator and 0cc exhaust. Leo Vince makes one 70cc exhaust in the ZXR. Several no name brands on scootertronics will do every bit if not better than Leo Vince.
The Yamaha Zuma responds well to a simple carb and air filter upgrade to 17.5mm with use a 19mm or 22mm Dellorto for 70cc kits with exhaust.