What happens if 10W-40 grade oil is used instead of 10W-50 grade oil in Royal Enfield Interceptor 650?

Royal Enfield Interceptor 650 is a cruiser bike available in Indian automobile market. The recommended engine oil for Royal Enfield Interceptor 650 is 10W-50. The difference between 10W-40 oil and 10W-50 oil is that 10W-40 oil is less thick and sticky than 10W-50 oil. Being viscous, 10W-50 performs