'87 ATC 250r motor/school motors w/ Vin number

[hrc200x]

A few years ago I asked board members to look up a vin on a motor that came in my '89 trx 250r. Hoping maybe someone has some current info on it, can prove that it is or is not a '87 atc motor. What they found back then was that part of the number says its a '87 motor, and the next part of the number says its a ATC motor. The number is TBO6E-6006250

I took off my pipe today to put on a Bills, when I removed the stock one I noticed a number engraved into the head, appears to sloppy to be honda, did a school do this to try to keep track of the motors, or was this done by the guys that removed the engines back in '87 so Honda could keep track of them, but then again, why not just use the vin number. Anyone else with school 350x or 250r motors seen anything like it?

[x.system]

TBO6E is on all liquid cooled 250r motors and the number 8006250 falls in between 8000015 and 8008442 making it an 87 TRX motor.

The 85 atc was TB06E-2400001~
86 atc was TB06E-2500001~
86 trx was TBO6E-1000014~1021097
87 trx was TBO6E- 8000015~8008442
88 trx was TBO6E-8100014~8109454
89 trx was TBO6E-8200001~

I would think if they continued the sequence the 87 atc motor would start with 2600001.

[petesatc]

here is the 87R chassis and engine numbers from my 87R parts book as you can see the number starts with 8600050 so deffo not a 87 engine...