Customs Bonded Warehouse India or Nepal.
 

Does anyone know if a Customs Bonded Warehouse in India or Nepal.

I would head to Nepal where customs officers can be a lot more flexible when it comes to carnets, speak to them nicely and they might let you in without stamping yours. India tends to be the opposite and strictly enforces the maximum 180 day rule.

apparently the carnet limit for staying in Nepal is 6 months, however, I left after 9 months, and nothing was said or noticed at the border, when I crossed into India.

Also Nepal don't record anything in your passport about the vehicle and carnet, so if you need to leave the bike in Nepal and fly out, this isn't a problem.