Pit Bike Engine Size & 50/70 Engine Size
TBolt USA Tech Database!

Pit Bike engines are based on Honda 70 type engines 

These engines are currently in Honda CRF50 , CRF70 bikes
The 2 main motor mounts and bottom 4 mounting points(pegmounts) are the SAME on all Pit Bike Engines
Pit bike Engines fit in All China Pit bikes and Most older / current Honda bikes with horizontal OHC engines (NOT KLX110 or DRZ110)
Major sizing differences are
1) 90-110cc is 9mm taller at the head due to longer cylinder
2) 120-UP are 15mm taller due to longer Cylinder
3) the CRF50 has a recess in the Clutch cover to allow the bottom pegmount , Pit bike engines do not
But there are many simple bolt on Pegmonts that can be installed

This is a sizing diagram for Lifan 50-70cc - Same as CRF50/70

Motor Mount info:

Pit bike Engines are approx 11in Wide (280mm)