Chinese 4 stroke GY6 50cc with 100cc BBK. Can't exceed 35MPH  By  deejae (Read 11,060 times)

did you upsize both front and rear tire or just the rear
because if it's both it's going to register as a slight speed reduction
do to speedometer ratio change and friction load increases
but the taller tire will give you 4 to 5 mph but wether it reads or not depends
on the front