GY6 Engine Upgrades
GY6 Honda Clone engine used in most Chinese and some Taiwanese scooters in the 139QMB 50cc engine and the 157QMJ engine for the 150. Slight difference from each manufacturer has been found as Vento QJ four stroke is difficult to put an 82cc cylinder kit but the 72cc seemed to work and this was found out by QJ makes pep boys engines and scooters also and was found while upgrading pep boys brand. All other 139QMB engines have been found to take up to 85cc kits. With a cylinder/head kit 20mm carb with large intake, Uni Filter, GY6 V850 exhaust, DR Pulley 161301 clutch, MRP variator with Dr Pulley slider weights at 8gram plus Polini kelvar belt makes one fast scooter. This version of the GY6 50 engine will climb hills with ease and get a cool 50 on a straight without wipe open throttle. This engine on a 12” wheel medium size frame gets the job done. Along with a chrome muffler chrome grips can be added with high performance throttle body. With the wider tires plus front and rear disc brakes this scooter rocks.
The GY6 157QMJ has a couple of different versions that are at least better or worse with the 1P57QMJ engine used by Tank and Roketa have problems with 59mm cylinder kit fitting bolt pattern and case. It could be possible the 58.5 would fit but have not tried that one. The QJ Vento, Strada and Keeway scooters use the best case and engine parts on their 150cc, 155cc 167cc engine accept every upgrade from carbs and cylinder kits to clutches and roller weights, shocks, everything all can be added., The Strada RX200 all years responds nicely with exhaust kelvar belt and dr pulley weights as an easy upgrade with results and by adding a jet and air filter really brings iyt around, the 2008 model is 167cc so upgrades are due mostly with DR Pulley clutches and variators plus 9gram slider weights. Upgrading a 150 starting with the trans add Dr Pulley clutch Variator Slider Weights with Kelvar belt Malossi or Polini, leave compression spring stock using a MRP Chrome Clutch bell with chrome vented trans cover the trans is complete. Top end off with a 59mm head and cylinder kit, 32mm carb with large intake plus high performance air filter from MRP. See the thing is you can do to a scooter or a go cart for slamming results.
