2004 Official factory service manual for Yamaha YFZ450S ATV Quad., Page 151Get this manual
CAMSHAFTS 2
Install: clips intake camshaft cap exhaust camshaft cap camshaft cap bolts
10 Nm (1.0 kg, 7.2 ft lb)NOTE: Tighten the camshaft cap bolts in stages and in crisscross pattern, working from the inner caps outCAUTION: The camshaft cap bolts must be tightened evenly or damage to the cylinder head, camshaft caps, and camshafts will result
3Install: timing chain tensioner