What is the size of the fuel pump on a 86 Honda Accord?

Don't know what you mean by what size. You are lucky in that you Honda fuel pump can be accessed without removing the fuel tank. You will find an access panel either in the trunk or under the rear seat.

Answer

i have an 86 Honda accord LX 2.ltr and my car does not have access points inside the car i had to drop the gas tank to get to the ful pump it can be done by one person i did it with a pair of needle nose plyers channle locks and Phillips and standard screw drivers if you are not mechanicly inclind do not try to do this there are a few hoses you need to un hook to drop the tank if you pull the drian plug and drain the fuel into something you cna handle the gas tank on your own its not hard