My starter was becoming progressively more sluggish. It would suck the 6 month old battery down rather quickly, turning over very sluggishly or not at all. All my tests led me to conclude the starter was bad. Jumped solenoid, cleaned up all connections. fully charged battery made no difference. It never turned briskly anymore. I took the back cap off the starter and check brushes, cleaned things up. No change. So, I bit the bullet and ordered a new starter. Installed it today with assistance here from Nick. New starter does the same thing, if not worse. Very slow to no turnover. What else could it be? I see sprag clutch failure is common. Mine seems to be working. The starter does not free wheel. Can the sprag fail in a way such that it puts an excessive load on the starter?

I can't see any way that the sprag can load the starter but when they wear they slip so that although the starter is turning, possibly fairly quickly, the engine only turns over slowly and is reluctant to start. This is sometimes accompanied with a sharp bang if the engine kicks back against the sprag which accelerates the damage to the sprag.
Since fitting a new starter to my 907 it turns the engine over very quickly. At least I know my sprag clutch is good.

Test w another battery.

Not so much the sprag but the idler gear between the sprag and the starter can cause drag. More commonly tho are electrical issues which can be pinpointed with the appropriate voltage drop testing

The starter is not turning quickly, the idler gear seems to move easily, so I think that rules out a problem inside the motor. I may be embarrassed to find it has been the battery all along. It's a newish AGM, charges well, holds a charge (my battery charger does a 12 hr test) and I have it on a trickle charger. The voltage drop is at the battery, but I interpreted that to mean the starter had high resistance and was drawing excessive power. I guess I should have refreshed my memory on testing starters.

Anyway, I can now get the left cover off in 20 minutes.

Thanks for your input.

My SS had starting issues ,looked to be a dying battery ,so I hook up jumper leads and being lazy I put the + jump lead on the solenoid terminal and the - on the frame . The starter spun real fast ,bike starts ....sooooo must be the battery, I fit new battery but bike still no start ( back on the jumper leads) , mmmmm must be the starter brushes , so in went the new ones. Bike is no better . It was a crook earth lead ( battery - to frame lead ) , and when I put - jump lead on the frame I bypassed the crook lead sending me down the wrong track
The brushes are the same as Suzi GN250 ( and heaps of others....very common starter ), as is the o/haul kit......available on ebay for bugger all...even freight free from China .

I need to get to the main ground. it's rather buried under the tank. Removing the rear fairing side panels is a bit of a Chinese puzzle. Learning as I go. Update: Oh, the ride side panels were very easy...even covered in the shop manual. Although I did the starter replacement w/o removing them, it would make it much easier as you can get to the connectors for the crank and timing sensors, so you don't have to remove them from the left side engine cover. Also, the main grund is accessible for cleaning.

I don't have a new battery yet. I used a compact lithium jumper and got the starter turning fast enough but the bike wouldn't start. Then I noticed the fuel pump was not energizing when I turned the ignition on. It always did before. Also, when I pulled a spark plug and grounded it while trying to start, there was no spark. ARGH! I thought maybe I had killed the crank or timing sensor when removing/reinstalling the engine cover. But they both read 680 Ohms and showed a small spike while cranking and I could see the tach jump while cranking. I swapped relays and the fuel pump came to life but still no spark. The relays seemed to click, but activation of fuel and ignition was inconsistent. I opened them up and manually closed them a few times. Then the bike started and ran, but the activation remained inconsistent. I will blame the relays, although I will look at the ignition switch.

New battery tomorrow and some replacement relays after I figure out what will work for the double break and make units. I think the 82 Porsche 928 has one of those for the fuel injection system.

When the bike wouldn't start despite a fast turning starter and motor, I got pretty frustrated and thought I might have created a catastrophe. Like one of your member's sigs says, Ducati, making mechanics out of riders. So I see.

Bad connection at ignition switch is not uncommon on these bikes.

Cleaning the main ground is ok but have a good look at how well the terminals are crimped onto the cable. An auto sparky shop should be able to supply double acting relays,and I would replace them if any doubt . Dodgy relays can sometime cause weird ,seemingly unrelated symptoms. Sometimes you just have to walk away from it. Getting frustrated and impatient whilst working on Ducatis is quite normal ....but not all that helpful

I plan to do the ignition switch wiring mod (relay removing full power passing through the switch). Great idea in the FAQ. BUT, with the relay oddities, I want to examine the ignition switch itself. How is it removed?

Looks like the ignition switch has some security type bolts holding it on. I see threads inside the bolt head. It looks like you can pull off the electrical plug...I think I may have broken one of the retaining tabs on the plastic plug housing. I only got it partially off. I'd rather take the entire switch off to work on it, but I don't know what tool I need.

If they are security bolts you will have to drill the heads off

Usually secuirity bolts are soft enough you can slot them with a sharp chisel and a hammer and the back them out with a screw driver.

BTW, the battery is definitely bad. New one on order. Even though it was a 6 month old battery, I learned AGM batteries are very sensitive to overcharging. There was evidence that the damage had already been done when I picked up the bike from the PO. It had seemed to work fine a week earlier, but that day it began to exhibit the serious sluggishness which only got worse. I initially was convinced it couldn't be this newish battery. And I had encountered a starter once before that made it appear the battery was going bad. So, even though I ran through voltage drop tests, I completely misinterpreted them to fit my theory. I replaced the starter, as mentioned in the first post, with zero improvement. Then relooking at the voltage drop at the battery, the light bulb in my head finally lit. One of my faults is that I am slow to give up my assumptions. Live and learn. Anyway, I am now almost an expert on left side cover removal.

Before I fault the ignition switch and/or relays for their seemingly erratic behavior, I need to install that new battery.

Cheers,