Engine size 1983 Honda Accord VIN # JHMSY7431DC810237 Can't find engine size Double checked VIN code and it is correct

Check the glove-box. Typically Honda places a small sticker on the back side of the glove compartment door. There should be two different sets printed on the sticker. The set with five digits is your radio code. Use the radio preset buttons to enter the code. If you have done it correctly, the radio will come on instantly with the factory default presets.

Depends on the 8th digit of your VIN code = engine size.

VIN "6" - 8cyl. 6.0L 4BL (4 barrel carbureted)
VIN "8" - 8cyl. 4.1L TBI (Throttle Body fuel Injected) (95 % of 83 Cadillac Fleetwoods)
VIN "9" - 8cyl. 6.0L TBI (2% of 83 Cadillac Fleetwoods)
VIN "N" - 8cyl. 5.7L MFI (Multi-port Fuel Injected) Diesel OHV (Overhead Valve)
(3% of 83 Cadillac Fleetwoods)

Check this website and double check your vin number to see if its correct. That way you can determine what you have for your engine sixze. If your engiune number had CE at the very beginning it would be a replacement Crate Engine. Yours is not a crate engine replacement as far as I can tell from the numbers you posted
http://www.nastyz28.com/decode.php

Sadly:
There is only 2 options.
1. Your radio code is in your paperwork for your car (Its on a hard plastic card) Find it.
2. Take your registration to Vin and Ser Number for your radio to your local dealer.
These codes are a guarded secret and no one code fits all.
Hope this tip helps guide you in the correct direction to solve this problem.
R/
David

Yes this will work if it says direct fit oe replacement and not universal. The universal replacements never work because you have to cut the plug off of your and wire it on the new one. The Engine code is the 8th character of the vin. You can also look under the hood on the engine label and get the code there.

If your talking about the VIN, call your local honda dealer(service dept.)

Check owners manual, made written on inside of covers or on radio pages.  IF not check inside of glovebox for four digit code.  If not luck, remove radio document all number, ie serial number on unit and call local honda dealer.  They must run the VIN and radio info back to the motherland to get lock code.

If your radio is coded, make sure you have the code and know how to re-enter the code in the radio.

• Remove both battery cables and secure them away from the battery terminals.
• Detach the E, F and N plug from the the alternator.
• Slacken the alternator mounting bolts and move the alternator forward towards the engine.
• Remove the drive belt.
• Now undo all the mounting bolts and lift the alternator clear of the vehicle.

Re-fitting is just the reversal of the removal.

Help to find a manual on 1983 honda accord, for engine major repairs.