When I first got my airhead less than a year ago, it was in dire need of an oil change. Not knowing any better, used the same brand oil I use in all my other motors.....AMSOIL. I used a synthetic motorcycle oil that AMSOIL makes. I also did an oil filter change at this same time too. However, after further educating myself from other airheads, I discovered that synthetic may not be the best thing for an airhead. So, Im now going to do an oil change and put some good 'ol fashion black gold oil in the bike. So, I've done the non-synthetic to synthetic transition, and there are some nice procedures clear out all the old oil and get a fresh CLEAN oil change with the synthetic. I however, have never done the "backwards" transition. Two questions..... 1)am I ok with just draining the synthetic and then adding the normal oil? 2)am I ok not changing my oil filter? (I know with normal oil changes, not swapping filters is an accepted procedure with airheads...just not sure in this case) **note, likely less than 200 miles on synthetic and on this oil filter.