S4R Won't Start - Getting me Down - Part 2

02-06-2019, 05:06 PM

Continuation (See Part 1)

At this stage, my attention is drawn to the strange starting nature of the S4R which I have always found “curious”. It’s like with ignition on, kill switch on, when you press the start indent it seems that you are not actually in control – ie: it always strikes me that something else is monitoring and controlling this circuit. (Yes – you can laugh – I have since discovered that the S4R utilises a Servoignition System – do all Ducati’s use this???)

Long story short – I ride Harley’s and old Triumphs – so I am convinced there is a problem. I disassemble the kill switch/starter indent thinking bad contacts, (that was fun….. don’t try it….), all contacts look good, I spray with electrical contact cleaner/Vaseline on plastic sliding faces and reassemble …..I found nothing wrong.

I perform voltage drop tests and find nothing untoward (I think.) 13.44V across battery terminals when standing, falling to 11.38V with engine cranking. I note however that the voltage drops to 12.80V just by turning on the ignition. I then discover with the multi meter that I have a “continuity” reading across the starter motor between the starter body and the positive terminal post. Bingo!! I am thinking, I have field or armature windings failing in the motor or something – I’ll change it.

Are you all rolling about laughing about now….?

So – after discovering that a starter motor for a S4R costs more than a starter motor for a V8 Range Rover Sport (seriously…!!) – I buy one – but I am sorry - it did not come in a Ducati box.

In the process of gaining access to the starter motor, with the alternator and side cover removed, I crank the engine to see if there is any slippage, or anything sporadic going on with the starter clutch. All appears good and I leave alone. I install the new starter motor, (which incidentally also shows continuity between the positive terminal and body when on the bench…..)

It still doesn’t start – anybody looking for a perfectly serviceable starter motor for a S4R…..???

Final observation – I KNOW we should not do this, but even after spraying WD40 directly into the combustion chambers via the throttle body with the butterflies held open, when I go through the start sequence, the engine does not fire. (Yes – the cam belts are intact..!!!)

I really do give up – I just cannot think of what else to do.

Please, anybody got any ideas???

02-06-2019, 05:06 PM	#1
Dilkris Guest Posts: n/a	S4R Won't Start - Getting me Down - Part 2 Continuation (See Part 1) At this stage, my attention is drawn to the strange starting nature of the S4R which I have always found “curious”. It’s like with ignition on, kill switch on, when you press the start indent it seems that you are not actually in control – ie: it always strikes me that something else is monitoring and controlling this circuit. (Yes – you can laugh – I have since discovered that the S4R utilises a Servoignition System – do all Ducati’s use this???) Long story short – I ride Harley’s and old Triumphs – so I am convinced there is a problem. I disassemble the kill switch/starter indent thinking bad contacts, (that was fun….. don’t try it….), all contacts look good, I spray with electrical contact cleaner/Vaseline on plastic sliding faces and reassemble …..I found nothing wrong. I perform voltage drop tests and find nothing untoward (I think.) 13.44V across battery terminals when standing, falling to 11.38V with engine cranking. I note however that the voltage drops to 12.80V just by turning on the ignition. I then discover with the multi meter that I have a “continuity” reading across the starter motor between the starter body and the positive terminal post. Bingo!! I am thinking, I have field or armature windings failing in the motor or something – I’ll change it. Are you all rolling about laughing about now….? So – after discovering that a starter motor for a S4R costs more than a starter motor for a V8 Range Rover Sport (seriously…!!) – I buy one – but I am sorry - it did not come in a Ducati box. In the process of gaining access to the starter motor, with the alternator and side cover removed, I crank the engine to see if there is any slippage, or anything sporadic going on with the starter clutch. All appears good and I leave alone. I install the new starter motor, (which incidentally also shows continuity between the positive terminal and body when on the bench…..) It still doesn’t start – anybody looking for a perfectly serviceable starter motor for a S4R…..??? Final observation – I KNOW we should not do this, but even after spraying WD40 directly into the combustion chambers via the throttle body with the butterflies held open, when I go through the start sequence, the engine does not fire. (Yes – the cam belts are intact..!!!) I really do give up – I just cannot think of what else to do. Please, anybody got any ideas???