I was picking up a few quarts of oil for the break-in period (brand new 426) and the dealer told me to go with a synthetic blend even for break in. I've hear quite a few horror stories from people who have run synthetic oils for the break in period (on other bikes, not the YZ) but the dealer pointed out that the Yamalube 4R is synthetic and is recommended from day 1 (this dealer doesn't carry yamalube). What do you guys think? He was selling me the oil for the price he paid for it since I just bought the bike from him so I don't think that this was a proffit driven suggestion. Thanks!