It is an 86 motor, based on the number you posted. Why would you think an 86 motor is junk? Aside from a few differences, all years are basically the same, and you can interchange most parts between all years. The 85-86 motors are short rod motors, and the 87-89 motors are long-rod motors, there are slightly different gear ratios on the 87-89 motors also.
2014 CRA Senior II and Buckeye Series champ
2012 CRA Senior II champ
2011 CRA Senior II and Buckeye series Harescramble Champion
2009 CRA Senior II and Buckeye series champ.
2007 CRA Senior II, and Buckeye series Harescramble Champ.
2003 Lonestar 250R
2001 Lonestar 250R.....now a 310
1986 TRX250R (restored to new)
1986 TRX250R (still in pieces)