Had my C400X since August 2020 with just 3000 kms. Has never stopped an awful vibration since purchase especially at 30 kph with slight throttle. Whole bike shook and after many attempts of trying to prove a problem with BMW dealer... I finally refused to ride it unless it got sorted as it became really bad. BMW striped the bike and found the engine mounting was designed wrong and sent a replacement over Christmas that took 3 weeks to arrive and involved a big strip, luckily the replacement throttle cable assembly was done at same time, all under warranty, luckily I have a 3 year BMW warranty here. Can report bike is 100% better and is totally different to before. Rides like a normal scooter. Now plagued with the BAD closing seat that is worse after the rebuild, but despite BMW trying to tell me how to press it closed, wriggle it to close and slam it, still refuses 90% of the time... stupid design!! Anyway hopefully fixed this week as new catch on order!! I tried to tell the dealer there is a modified seat available but it falls on deaf ears!!! Love the bike, fuel economy is beyond excellent, got the digital dash all connected to helmet and Nav, fast enough for me, good comfort, expensive but worth it. No battery issues, and it has been left for weeks... Keep at the dealer if you have an issue is my advise. Jim