well just looking down from the top,i took inj 3,4,5 out and 4,5 the ball looks somewhat square on the tip with rounded edges,also they had a black steel color to em,the #3 the ball was more rounded but not to much more then the others,also it had a somewhat whiteish gray appearance to it.sizewise they looked pretty much the same.you say the balls should be in the middle of the prechamber,that is not my case they are all sticking maybe a 1/3 the way into the center.i do have some pics but don't know how to download i could send em to ya?as for the pump,if the timing mark on the crank is the pointer towards the top,just eyeballing it the lug thru the bolt hole on the pump looked dead center,so i guess i'll have to check out mb. doc about that riv tool.