When I swapped my cam on the 90 I didn't put the chain on in any particular way. I wasn't aware that certain links on the chain needed to be placed in certain areas. I just lined up the dots on the cam gear, marked the belt, taped the belt in place when I pulled the cam loose (so it didn't go slack over the crank), swapped the new cam in, in the exact position and put it back together. I did take pictures before tearing it apart and b/c I swapped the cam, I pulled the gears off but made sure I put them back exactly as they were. The pics helped because I could see what position the cam lobes were supposed to be pointed at TDC.