i've got a 1983 vf750 and it's got a problem. the bike starts well, and idols good, even rides good until it warms up. once warm- it runs horrible, wont idol and the tachometer stops working. the pulse generator was giving bad readings, so i changed it with one that gives good readings. now i am confused. can anyone please help me to diagnose this?
ok- it heats up and runs like hell. no spark to 1&3 with good spark to 2&4... the coils seem to test well. i switched the Spark Unit clips and when i did the problem reversed itself (spark to 1&3 no spark to 2&4). is there any way to make sure its a spark unit???? it's the spark unit with the white clip, is this the one that attaches to the tach?
All of the failed CDI's I have dealt with just flat oot failed, I would inspect the wiring to the suspect unit and the circuit board as well.
Your CDI box on 1/3 is bad. When mine went the tac would only go up to 2500 and 1/3 was dead. Seeing you swapped the boxes, which is the way to troubleshoot them, and the problem switched to 2/4 proves it's the 1/3 ignition box. Yes 1/3 box controls the tac and 2/4 controls the fuel pump.
