if you can't change the RPM of the motor, you have to change the gearing of the chain drive. Fit a smaller sprocket to the motor to slow the conveyor down, or a bigger to speed it up.
with stock gearing 78 mph
140km/h With stock gearing 50-53 mphWith stock gearing 60 mph
With stock gearing around 60-65 MPH
Stock gearing 60-62 mph
With stock gearing 50-52 mph.
stock gearing 60 mph
makes it go slower
With stock gearing top speed would be 50-52 mph.
Possibly if gearing were changed. With stock gearing top speed would be 50-52 mph.
With stock gearing 70-73 mph
Depends on the year, engine, transmission, gearing, etc...