126cc robin
 

I got my kids a manco hyper awhile back and they love. My question is about the 126cc robin engine the engine runs fine ,it actually starts and runs great , but it has no low end torque. If they stop on any type of incline it won't pull hard enough to go. Is displacement as big to torque on these motors as it is in a car ? Ive looked at the 212cc preditor motors and wonder if that would be the easiest fix ? The 5 HP Briggs has 205cc why is the robin so small ? Any input would be great.

The Preditor engine would be the cheapest way to increase HP- but to resolve the hill climbing ability you'll probably have to upgrade your clutch or go to a CVT (TAV2). The 5 hp rated Robin is a great/reliable/powerful engine-but a weak or failing clutch system could make any amount of HP do the same thing.

I was thinking about the clutch being weak but it's brand new. Although it is a centrifugal clutch not a torque convertor . I was thinking that i would replace the motor before the clutch.

How many tooth sprockets are you using? Engine and axle?