Check out this same topic,it was covered with lots of good advice in '04 and '02, and I will add some of my own.
C.A. borders are still generally a lot of paperwork and can take from a half hour to 3 or more, the crossing from El Salvador to Honduras at El Amatillo being the worst case scenario, as everybody else reports too. Honduras/Nicaragua are slightly quicker. The best crossing to Honduras is indeed at Florida Copan because of light traffic with a high ratio of tourists which got their attention.Most of the other entries are reasonably quick, in C.A. terms.
The Copan entrance is smart enough to provide a big sign outlining the exact procedure to follow,in FOUR steps which apply to every border crossing in C.A.
Step 1 Migracion- tourist card , fill out
form, stamps in passport, pay
Step 2 Transito -get temporary import per-
mit ,stamp in passport, pay
Step 3 SEPA ,or OIRSA, or Cuarentena or
Fumigacion- get bike sprayed
with insecticide, get a small
certificate, pay fee.
Step 3 is not carried out at
all of the borders, the CA4
(GT,ES,HON and NIC) may rec-
ognise entry into one as
being proof of having been
cleared of insect pests.
Step 4 Aduana, get all papers checked ,
have luggage checked, Finish !
The difficulty of the process at any border is easily gauged by the number of guides who chase after you offering their "help". At El Amatillo they will accost you several km before the actual border in El Salvador where all the trucks start to line up. If you don't speak Spanish well a guide MAY be of help ...but... many of them are con men who will try to slip you phony documents and tell you you have to pay a fee for something .Don't believe them. Hire the young kid who is less apt to have learned all the gimmicks yet. Agree to a price, to be paid AFTER you are done. Never hand a guide all your papers expecting him to get it done for you, this is an invitation to get ripped off for phantom fees. You should be the only one handing documents and fees to officials who must give you receipts. The guide needs only to lead you to the various wickets.If you speak Spanish , find the Migracion wicket and ask them to point you to the next one .
Belize, Guatemala, Costa Rica ,Panama borders are much easier, better organized.
If you are going to be travelling back from Panama, you will have to go through all the routine, and fees again, except for Guatemala and Costa Rica.
If you plan to take the alternate route from Panama back into Costa Rica ( either the Panam highway or the route from Bocas del Toro,Changuinola area to Sixaola ,CR) tell the CR customs so before you leave. They will then give you a photo copy of the documents you handed in so that you can present them at the other entry and expedite the process ,no fee. If you don't use another route back they will keep your paper on file and give it back to you.
Also if you are doing the round trip be sure you keep the Guatemalan SAT temp.import document with exit stamp to show on your return or they may not know your bike was legally out of the country, not sold in GT.
In every case make your border crossings early in the day so as not to get snagged by bureaucratic bungles that could drag you into the night. Be patient, have a sense of humor, if you start screaming and ranting they would probably make you suffer more yet.