hi vikram, i have traveled to leh from chennai in august 2014 with rented bike from delhi(with 3 more guys). We were aware of this ban on rented bikes but still took risk. We have been to nubra and pangong as well but no one has stopped us and questioned ever. What I heard was, their target is to stop big groups which were organized by tours&travels. I am not suggesting you to go with this option but may be you can take some risk based on the feedback from travelers after the season starts. Leh-Manali can be done easily in 2 days if you start early in the day. kargil-leh is one day with any number of breaks. its an awesome road to drive. what i understood from our trip is that,starting early in the day is very critical to maintain the schedule.