[mortenmorfar]

Hello, im looking at an 99 SV650 for a friend of mine, it has some trouble with the ignition
when you are riding and it reaches 8k rpm, it starts to sputter/misfire, and the tach starts to jump around,
sometimes it doe's this at lover rpm too.
He have replaced the coils and plugs, which seemed to "cure" it for a couple of rides, now it's acting up again.
Could it be the ECU that's going bad, are those models known for that ?, or do you have any other suggestions ?

 

[dpapavas]

I don't know much about SVs, but you might want to measure the voltage at the battery, as you slowly rev up the engine in neutral. If it exceeds 15.5V or so volts as the engine speed rises (up to say 8k rpm), you probably need a new R/R. If that's the case the overvoltage may be causing the problems you observe (along with potential damage to the electrical system).