Set the crank to TDC, marked by a T on the fly wheel, then line up the marks on the cam sprocket level with the top of the head with the cam lobes facing down. You are now in time.
It is that simple and it can't be changed without changing the key on the crank.
2001 416EX with Sparks X-6, FCR 39mm, ELKA Triple rates with cans, Burgard +3+1 A-Arms, Elka Linkage with Custom Axis Rear shock, Denton Steering Stabilizer, WISECO 87mm 11:1 with Hotcams Stage II, FDO Heavy Duty Head Studs, WB Rev Box, K&N Air Filter, Cascade Parking Brake Blockoff, AC racing Pro Peg nerfs, Renthal Sprockets, Renthal bars, DG bumper, DG Swing arm Skid, RPM 2+2 axle, speed locknut, Magura Jack Hydraulic Clutch
1988 TRX350R ported by NRPD, ESR TRX5, PWK 38mm A/S, Gibson Long Travel A-Arms, Elka Quad Rate longtravels, Laeger Swinger, ESR reed block
2007 CBR1000RR, Akrapovic Full Race, Comp Werks FE, DynoJet PCIII, ShoGun Sliders