Krone KR130 Axle Beam

I recently bought an older KR130 from an estate dispersal and am in the process of getting it into working condition. While running, the slatted chain doesn't clear the axle beam which I can see is bowed. A neighbor suggested that the bowing is by design to counter the weight of the bale, like a large trailer. Should the axle beam be perfectly straight? If not, how could I add more tension to the chain so it clears?

 

Thanks

 

 

Krone KR130 Axle Beam