Hey, I just bought a 2005 400ex and am new to this site. I bought it with a brand new engine in it. I have a few questions about it. What is the best oil to run in it and is full synthetic ok for it or not? Also when its running it makes a small clicking sound coming from the engine, and im not sure it thats normal. last thing is its missing the larger of the two bolts for the oil filter cap... does anyone know the size?