Motorcycle Repair: fuel pump, fuel pump relay, pain in the arse

Question
hello, i have a 1983 honda shadow vt750c, the fuel pump wont prime the jets when i turn the key but the bike runs fine once theres fuel in the carbs.. its a pain in the arse to start but runs good.... i got a new fuel pump relay cut off, and a check unit, and i tested two fuel pumps. one which i know for sure works. and it still wont pump gas to prepare the bike to be started. im sure there is a general idea would have on how to trouble shoot this.. and your the only one available for questions. thanks

Answer
I do not know much about these bikes, but I'll have a stab at helping you.  You've tested fuel pumps, and your have checked that the fuel line to the carbs is clear.  Is there a return line from the carbs back to the fuel tank?  Check that that is clear too.  Is there a shutoff mechanism for the fuel based on vacuum?  I think the first thing to do would be to get a service manual for the bike so you can check in a logical manner.  Let me know what you find.

Good Luck,  Jan