As the motorcycle moving with a constant velocity ascenda on the overbridge of R, then the normal force on it,

Here, the normal reaction is clearly dependent on the angle $\theta$

$\mathrm{R}=\mathrm{mgcos\theta }-\frac{{\mathrm{mv}}^2}{\mathrm{r}}$

$\mathrm{R}\propto \cos \left(\mathrm{\theta }\right)$

$\text{ When }\theta \text{ decreases. }R\text{ increases. }$