I have been looking on ebay all morning for parts for my 87 bigred that the bottom end is locked up on.

alot of the parts I am finding are listed for the 85-86 models but dont mention 87, are there any significant changes on the 87 that would cause parts from the earlier models not to work?? also are the 250es and the 250sx the same engine are what is the differences in them??

 

The bigest difference in all three is the starter. Honda made at least three different types. Make sure you match the starter gears for the correct motor. The rear end should be the same for the 86-87 but different for the 85. Electrics are different. Also the cam chain tensioner on the 87 is different. Almost sure the bottom ends are the same but better check that out.