It was located at the plug of 12V supply to starter solenoid, that one that activates the solenoid. View attachment 6250
No scale to the photo so take a guess at some electronic component: either a diode, or possibly a capacitor with a broken leg ?
What does it do? Since forever I never seen it connected like in your picture? It was there plugged in to one of the legs and broken off the other. That is on carb monster.
Prevents a voltage spike travelling back down the loom when the starter solenoid disengages. Looks like the leg to the red/blue wire has broken off. The writing on it will help identify what you need. Try Maplins.
it's funny - these were standard factory fitment on most late 80's/early 90's Cagiva/Ducati range but I rarely see them on later models and i've had no problems on at least 6 bikes not fitted with them so function is a bit questionable.
Did some research and one guy on ST3 found it a bit up the loom inside it so harder to damage. As far as I can remember I did not have it monster for 2y, might be longer. Do not see it on SSie as well. Will try maplin tomorrows.
Depends on how the solenoid is driven. Generally on the older bikes the the solenoid is pulled up by the the starter contact so the diode is of no real benefit. However on a lot the modern bikes the solenoid is pulled up by a signal from the ECU. When solenoid disengages the magnetic field collapses creating a back EMF. The diode is there to prevent this spike cooking the ECU. Upshot replace asap and make sure you get it the right way round.
Replace ok got that so now maybe someone can tell me what rating for diode? Nothing of it's existence in workshop manual I have!
Don't know the rating for the diode Lucas, you will have to do some research on that. What is vitally important though is that when you do refit the diode it needs to go in the correct way! Maybe ask Moto rapido for rating, they will be inexpensive!
Well I have started searching for partial number I can see on my diode 4007 and got tow hits but later on realised they are both the same. Rating is IN4007 or 1N4007 so 1000V and 1A. Marlin does not have it so I guess eBay but it seems minimum I can buy is 25 and that is not a bargain as it looks as 25 is 99p but 100 is 1.49
Thanks D.M. if I had one fitted to a bike I would preserve it of course but can only speak as i've found. Also have to say although not an electrical wizard, there clearly more to the diode function than just protecting the ECU as the most popular fitment i've seen are on the Mito which doesn't have one - I think it is there to protect any semi-conductor circuitry with little tolerance of even minute fluctuation in theory? I've had no electrical problems after jump starting 748/996 dozens of times and not one of the four has/had a diode fitted across starter solenoid or anywhere else as far as i'm aware so maybe i've been lucky..
You should be able to buy a pack of 5 from radio spares they have shops and are also online, google RS its a fairly common diode
