Item #5 on the crankcase diagram.
1985 ATC250R is part number 22815-HA2-000
1986 ATC250R and 1986-1989 TRX250R is 22815-HA2-670
The 85 atc250r part is on the left.
Same wire diameter. Same number of coils. Color is different. Just bringing up slight differences for future atc/trx 250r restorations