IN 2005 the 25tooth Oil Pump gear sheared and head was ruined. Then in 2013 new weisco pistons, powder coat frame...Bike ran super - maybe 500 miles. This spring performance deteriorated, and too late... head was shredded again, and 25tooth gear was bent and 35 tooth Oil Pump Idle cracked in half (I had replaced ALL oil pump parts in 2013 with new parts). Engine is totally apart now. ALL oil passages from crank thru cylinder head were clean. So, I need a new complete head and Oil pump. Will replace CAM tensioners as they may not have been recalled (No punch mark in case). In 2013 I did use assembly lube and HONDA GN4 Oil. I now know to prefill 'cam bowls' with oil, and inspect on occasion and fill with syringe if need be. I will use the Rotella 10w-40 with ZDDP additive. Couple of questions. 1) Does the oil pump flow through thru the tube down to the oil screen, or vice-versa? 2) What forces the oil up thru the small passages, up the cylinder bolts to the head? 3) Does the cam chain bring most of the oil up to the head?. I want to ensure I get it right this time, and need to understand exactly what failed, as I am unsure if the head was oil starved, then the oil pump failed, or was it the other way around? Thanks a million, Bob.