Ducati Monster Forum

2004 620 owned since new, I think it has 48k on it now. Service is up to date.
Usually the bike fires up fine, but randomly it will just crank won't start up. When this happens I can roll it down a hill in my garage and pop the clutch and it always starts this way.
I'm really at a loss with it. It's completely random but only happens on cold starts. The bike still has the immobilizer but the light goes out like normal when this happens.

Hello,

random happenings are the worst... hard to diagnose because we never know when next time is. Bad connectors somewhere (!) can affect almost every function on the bike - including starts. Battery might be bad and/or draw so much electricity that there's not enough left for normal ECU function (possible or likely?)  Workshops/dealers can hook up their diagnostic tool to check all sensors and more. That might be a good start.

Have you done a search here? Find threads about "bad start" "can't start" "random issues" and that sort of topics. That can take some time, but is a great way to learn and to narrow down the number of suspects.

The good news is that since it only happens at cold starts, it probably is a somewhat limited number of issues to look for. Not EVERYTHING.

Thanks for the reply. Yes I've searched but haven't found anything with the same issue.

Start with fully charging your battery and getting it load tested.  Stopintime is correct that a battery can be strong enough for the starter to turn but drop below the voltage needed for the computer to be happy.  A shortcut would be if it starts with a jump.

Next step would be check the charging system and voltage drop in the starting circuit.  Do you have a multi meter and some electrical knowledge? 

Yes I know my way around a multimeter. Charging system is good, I'll see what the battery voltage drop is when cranking.
Thanks!

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Add a temp sensor to the check list.