From what I hear there is a long skirt piston for the 450 engine available - maybe ccm have chosen to fit this in the final set up - who knows ? has anyone asked that would extend engine life a bit - along with the fact they have dropped 1500 revs from the top end with the limiter, remapped the ignition and advance all of which softens the stress on an engine - one designed to be revved to the limit all out, so i would think those factors alone would extend the bottom end life by a huge amount, if they do fit the long skirt piston that would also make a massive difference to wear on the barrel and piston - still not sure about the 1.25 oil capacity seems small but I am used to bigger bikes air cooled etc - yet with the above softening of the engine the oil is not going to get the same pounding and burning and with high quality modern oil the life span is petty good, but with that quantity I would be changing it every 2 - 3000 miles anyway - top gear featured a car last year that had oil change intervile of 100,000 so maybe 5000 in a detuned 450 is not as bad as they say. The 15000 mile rebuild if thats a reality would be a pain but i assume its only top end - piston valves and guides - which would not be a show stopper in reality a days work - the word is that the bmw g450x was warrantied for 36 month as an enduro machine - thus the reason for the massive maintenance schedule from BMW could it be in place so that they maybe never had to pay out for a warranty claim ?.I also see that there is an aussie lad has done over 30,000 on a 52hp g450x without a strip down - maybe he doesnt ride that till its screaming for mercy - so maybe all the rebuild stuff is just hot air and wind - scaremongering about the unknown !. I dont know till i talk to them in a few weeks time at the factory.