why would the bike stall?

Question

1991 Yamaha zfr600 old battery didnt have right cranking amps but after jump would run just fine until you killed ignition. I got the real replacment battrey with the right cranking amps and the machine dies just after dumping it into fist gear. What on earth is happenning?????

Answer 1

--That bike has a side stand safety switch.
--If you put it in gear with the side stand down, the engine will shut off.
--Either the switch is bad, or the side stand is down when you shift.
--If the stand is up and the bike stalls, try this to temporarily
by-pass it, to check if that's the problem.
1) disconnect the switch
2) connect a jumper wire to both terminals (stick a paper clip in the connector).
--I forget which way the switch works. Try both ways.
--Change the switch if the bike doesn't stall while doing the tests.

Answer 2

Probably a loose nut behind the handlebars.