Sounds like the cam chain tensioner was out of adjustment and it jumped it's timing. Check to see if the guide is worn out, it'll have to be replaced too if it is.

12208-413-003 SEAL, VALVE STEM (ARAI) 1 $7.87
2 14101-436-000 CAMSHAFT 1 $46.49
3 14431-116-010 ARM, VALVE ROCKER 2 $22.64
4 14451-035-000 SHAFT, VALVE ROCKER ARM 1 $5.09
5 14451-149-000 SHAFT, VALVE ROCKER ARM 1 $10.11
6 14711-152-000 VALVE, IN. 1 $20.22
7 14721-176-000 VALVE, EX. 1 $42.38
8 14751-149-000 SPRING, VALVE (OUTER) 2 $3.20
9 14761-115-010 SPRING, VALVE (INNER) 2 $2.73
10 14771-107-020 RETAINER, VALVE SPRING 2 $4.76
11 14775-107-000 SEAT, VALVE SPRING (OUTER) 2 $2.29
12 14781-107-003 COTTER, VALVE (SANKO) 4 $1.95
13 90012-333-000 BOLT, FLANGE (6X14) 2 $2.09
14 90206-001-000 NUT, TAPPET ADJ. 2 $1.24