I recently replaced a 7 year-old AGM battery which I assumed was the culprit since the engine would not crank even with a full charge. Although the new Lithium iron battery was charged to 13.7V, the engine still would not crank. The starter relay would "click" when the starter button was pushed. There was also an audible "click" in the starter itself. I assumed that this was due to the starter engaging with the flywheel since I could see the clutch trying to turn slightly. I cleaned the electrical terminal on the starter itself, as well as the 2 terminals & the pin terminals on the relay. The problem still persists. I must admit that diagnosing electrical issues is not my strong suit -- that's why I need some of your expertise. To be specific, how can I determine for certain if either the relay or the starter itself is defective? Thank you for helping me with this. Kit
Put a short across the relays high current terminals with something capable of carrying the starter motor current. Don’t short these to earth or you might get more sparks than you bargained for and shit load of other problems to fix.
A common issue on these bikes is corrosion of the terminals at the ends of all the large diameter Battery and Starter cables. They really should be replaced with better quality ones. The starter is earthed through the engine, and a particular bad spot for cable terminal corrosion is the Battery earth cable to Engine connection. Try a jump lead from Battery -ve to the engine to test this, but ALL Battery cable connectors should be checked.
As per Macca's post - direct live feed to the starter live terminal from another battery, earthed to the bike of course and if it won't spin it could be Starter Motor Brushes? Fairly easy job to do in situ on these if you are handy with the spanners, but it can be a bit fiddly. I think we covered it in a previous thread on here. https://www.ducatiforum.co.uk/threads/starter-motor-brushes-replacement.100260/
Also when my superlight starter stopped working it was excessive corrosion on the +12v post on the starter . Water can collect in the rubber boot covering these . I had to replace the post & the starter brushes , they come as one part. You can allegedly swap these in situe , I found it fiddly enough doing it to the starter motor on a bench & not sure i’ve the patience to try it on the bike , & would suggest having the bike vertical on an elevated workbench is needed if you dont like lying on your back cursing. All the other advice about cleaning all earths /+12v terminals & having decent not aged brittle cables apply .
Is there something about the small wire/connection to the relay coming off / loose, did you check that? Cheers Gaz
Thank you for the suggestions. In addition to cleaning the terminals posts on the relay & the starter, I thoroughly cleaned the ends of the large cable running from the battery to the relay & the cable running from the relay to the starter motor. Also, I cleaned the battery-to-earth cable. Although there was no visible corrosion, I cleaned the cable ends with both emery cloth & electrical contact cleaner. As per Macca's post, let me be sure that I understand. If I short the large terminals on the relay (with, for example, a pair of pliers), I assume that I am bypassing the relay & providing power driectly from the battery to the starter. If the starter engages the flywheel & turns the engine, I can assume that the problem is the relay. Is my thinking correct? As 98 SPS recommends, should this test be done with another battery? To answer GAZ's question...the small wires to the 2 pins on the relay were tight. As a precaution, I unplugged the connect & cleaned the pins & the plastic connector. One other question...several YouTube videos suggest checking the resistance between the terminals on the relay in order to see if the relay itself might be defective. Should the relay be removed from the bike & tested on the bench?
It's not just the relay that's in question normally because (for example) the circuitry from the starter button on the handlebars can also cause the same result but as you got a "click" - as alluded to, then it's probably safe to say the problem is from the relay onwards. Have you tried piggy-backing an extra battery onto the bike battery? You could try this before you try shorting the two terminals out on the solenoid. I haven't read all answers in full but it sounds like most of the suggestions for checking have been covered. In the past i can remember even battery terminal connections can be the culprit. If you have some jump leads you can double up on connections to check earth etc. I usually go jump lead from earth on a good battery straight to the starter motor body and live lead from positive (very carefully) to insulated starter terminal but connecting earth on starter body last, as it will spark/erode. If starter churns engine adequately then you can immediately rule out starter and move on to leads, connections and solenoid.
Chris: What would be the advantage of piggy-backing another battery to the bike battery (since the bike battery is new & registers 13.7V)? I will also try your suggestion to connect another set of cables from the battery directly to the starter motor, thus, bypassing the relay. Does this have the same effect as Macca's suggestion of shorting across the high current terminals on the relay. Thank you for your help.
The easiest quick check is shorting the relay contacts if the starter doesn’t spin , then either the starter has got a bad earth, its duff , it’s jammed , or engine is ?, it could also be a duff battery with insufficient Cold crank amperes left in it. Good battery volts doesn’t mean good current & I’ve had batteries show green on reputable chargers that were still duff.
Macca: No problem with the battery. It's a new lithium-iron battery. I will try shorting the relay contacts.
...and be firm when you short across the high-current relay terminals with spanner/pliers/whatever. There will be sparks otherwise and hopefully a chugging engine
it's probably a waste of time, but if we looked back over all the threads on here where people swear by their battery's condition only to finally discover it's been the culprit all along, it's a small price to pay for ruling the battery out. PLUS - sometimes when a solenoid struggles, or a terminal/connector is not passing adequate current, the second battery sometimes enables a circuit to be made/starter to churn, and a quick check on any of the above for excessive heat immediately after attempt can sometimes reveal the culprit.
OK, here is what I have so far. First, I "piggybacked" a 2nd battery to the bike's battery. Still engine would not crank.Next, I ran a heavy jumper wire from the battery to the relay & another jumper from the relay to the starter. Engine would not crank. Next, I ran a separate wire from the battery's earth to the bike frame. Still no cranking. So I think that I have eliminated likely problems with wiring between the battery & the starter motor. Next, I "shorted out" the high tension terminals on the relay with a small metal bar. Still, no engine cranking. Similarly, I connected heavy jumpers from the battery terminals directly to the starter's positive terminal & starter's ground (thus, bypassing the relay altogether). And, again, no cranking. However, the starter seemed to engage the flywheel since the engine barely tried to crank. I suppose that this all points to the starter motor as the culprit. I would appreciate your thoughts so that I can feel confident that the starter motor needs to be remove & replaced/rebuilt. Thank you so much!! Kit
yes - starter it is, unless engine is seized - you have no reason to think this though have you? - you could try same test with plugs out as it might "try" a little harder but if you've done test as per post #9 then you have eliminated all but the above two options. Hopefully it's only brushes - sometimes a tap on the starter with (preferably) a hide or copper mallet or a block of wood might give the starter a short burst of turning energy and can be a sign that this is all it is.
You may also want to remove the spark plugs, just to give the starter an easier time until you find the fault.
Just a thought here @Kitjv Im presuming, from the year, your bike has carbs, not fuel injection? There is a possibility the horizontal cylinder could be hydro locked and no starter motor in the world will spin that over. How could it occur? A faulty float bowl valve permits the float bowl to overflow and the resulting constant trickle of fuel may find its way into the throttle body and run down into the horizontal cylinder. To check it, simply remove the spark plug from the horizontal cylinder, then try and crank the engine. If petrol sprays out of the spark plug hole there’s your answer.
