i had the same problem. After hosing my quad off before the rebuild i figure water got onto the terminals and caused them to cerode. What i did was took off the cables from both the battery and celinoid. Sprayed terminal cleaner on them and scrubbed them with a wire brush. after that the clicking went away and it startes everytime now.
02 CRF450
2002 Yellow 400ex
Yellow, Ross 10.5:1 piston std bore, Hotcam stage one, fmf Power bomb header, Hmf slipon w/ quiet core, K&N w outerwear, Whitebros Nerfs, Ac bumper, Itp .190 Rims, xcr Holeshots and klaws, Answer Pro-Tapers , Shockwears, PRM skids, frame gaurds, P-brake block off, Moose fly clutch lever, pro motion cable, no choke, ProDesign shifter
Xr50