Ducati Monster Forum

Moto Board => Tech => Topic started by: Bobino on November 15, 2018, 11:13:57 PM

Title: Bike tries to start after key shut off and kill switch engaged...
Post by: Bobino on November 15, 2018, 11:13:57 PM
I have 2001 Monster S4 and after I shut if off today by turning the key off, the starter kept going trying to start it and continued even when I engaged kill switch.  Finally stopped when the battery died.  Has anyone ever had a similar problem?
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 16, 2018, 04:40:10 AM
More than likely the solenoid is stuck closed.  Disconnect battery ground cable.  Take an ohmmeter and go from big cable to big cable on the solenoid.  Got continuity?  You need a solenoid.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: koko64 on November 16, 2018, 02:38:00 PM


Also check that the starter switch cluster isn't screwed so tight onto the handlebar so as to slightly distort the cluster body and stop the start button from releasing properly.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Bobino on November 16, 2018, 11:19:36 PM
I don't know what the schematic looks like for this bike, but wouldn't the ignition off and key removed interrupt the circuit for this.  Even with a bad solenoid switch, it seems like the ignition being turned off should have stopped this. 
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: koko64 on November 16, 2018, 11:30:24 PM
A fused solenoid will crank the starter with igniton off. The motor will turn over with no spark or injector activity with direct battery power. It won't run but crank until either the battery dies or the starter burns out.

With a cluster switch issue, the starter will stop when the ignition is turned off.

Follow Howie's suggestion as the solenoid can jam on via corrosion or "spot welding". Just follow the cables from the battery to the solenoid along to the starter by eye, a strong, direct power supply.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Bobino on November 18, 2018, 03:09:43 AM
Well, I got around to checking the solenoid switch today and it is fine...  Replaced the dead battery and everything is okay, for now.  I am assuming maybe the solenoid switch was stuck and now it is unstuck?  Who knows.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 18, 2018, 05:25:16 AM
They do that.  If it happens again the way to stop it is undo the negative battery cable.  And what koko64 said about the starter switch should be checked too.  It just needs to be tightened enough to not move.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Speeddog on November 18, 2018, 07:18:00 AM
If you have a good battery and a robust charging system, a stuck solenoid on a running bike can run the starter until something dies.
Customer just brought one in a few months ago.
Big Gen1 AGM battery was up to the task, as was the 3-phase charging system.
It ran the starter until it hucked some windings, wherupon it jammed, and the big wire terminal burnt in two.
That stopped the insanity.

Late model OEM solenoid has a nice pigtail and plug, not that miserable white 2-prong plug/socket.
Eastern Beaver maybe has the mating plug and bits?

Any electrical types out there.... can one put a circuit breaker in the path or some other device, maybe something a little smart?

Can that solenoid be replaced with giant transistor?
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 18, 2018, 07:53:08 AM
You would need onehelluba big circuit breaker, like, maybe the main breaker for your house.  AFAIK, there is no transistor that can handle that amperage at 12 volts.

You could do something primitive like this:

https://www.waytekwire.com/item/44075/Battery-Isolator-Switch/
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Bobino on November 19, 2018, 09:28:51 PM
Well, the bastard did it again.  At least this time I was home and was able to get the battery disconnected.  Ordered a solenoid switch.  I like that primitive battery key switch from waytekwire that Howie posted.  Don't know where I'd mount it though... I appreciate the input from everyone.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: NAKID on November 19, 2018, 10:00:03 PM
Quote from: Bobino on November 18, 2018, 03:09:43 AM
Well, I got around to checking the solenoid switch today and it is fine...  Replaced the dead battery and everything is okay, for now.  I am assuming maybe the solenoid switch was stuck and now it is unstuck?  Who knows.

Happened to my S2R800 years ago. I had to remove the cable to the starter. I happened a couple times, but then just stopped happening.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Bobino on November 20, 2018, 08:48:46 PM
Quote from: NAKID on November 19, 2018, 10:00:03 PM
Happened to my S2R800 years ago. I had to remove the cable to the starter. I happened a couple times, but then just stopped happening.

Did you do anything at all to fix the problem?  Or, did it just completely go away on its own?  I am going to replace my solenoid switch but, I am a tiny bit worried that it'll come back again even with the new switch.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 20, 2018, 09:55:05 PM
The problem is not all that common.  Never happened in over 80K miles and 13 tears on my old seven fiddy.  This can happen on any vehicle, usually as the result of many starts with a low battery.  Low voltage can cause arcing and excessive heat.  More common on motorcycles than cars.  Smaller part, smaller return spring.  Replace the solenoid and  [Dolph]
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: NAKID on November 21, 2018, 09:06:12 PM
Quote from: Bobino on November 20, 2018, 08:48:46 PM
Did you do anything at all to fix the problem?  Or, did it just completely go away on its own?  I am going to replace my solenoid switch but, I am a tiny bit worried that it'll come back again even with the new switch.

Nope, never did a thing. Just never happened again...  ???
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Qomomoko on November 27, 2018, 06:18:22 PM
My bikes has some starting issues.. but to not digress too much::
I am looking to replace the solenoid switch for my 2002 Duc Monster S4, part 397.4.001.1B.

To avoid spending $150 on an eom solenoid, what aftermarket options are there? I did search revzilla, bike bandit, ca cycle works and no go. Ricksmotorsporteletric website also had nothing. Found a universal from revival cycle website and looks ok.

I am replacing the starter cables from motolectric. I fried my starter a couple of years back and also fried my regulator. Regulator is no a  mosfet type, new starter, Shorai battery that does hold voltage above 13V and above 11.5v on a start. LOL... so much for a short story LOL. The issue is on cold days it takes several start attempts for  bike to start. I do warm the battery and give it time to recover after warm up. Think the new start cables will solve main issue, but figured might as well replace an almost 20 year old part that has seen abuse.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: koko64 on November 27, 2018, 07:46:46 PM
Maybe Electrexworld in the UK?
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 27, 2018, 09:18:13 PM
IMO, there is no reason to replace a solenoid that works, particularly with an aftermarket of unknown quality.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Qomomoko on November 28, 2018, 01:07:48 PM
with quality not always improving, that is something to think about.
I did not measure the voltage drop on the solenoid when it was installed.
Maybe I will just use it and measure the V drop. I have heard/reaad 1v drop is expected across the solenoid.
Title: Re: Bike tries to start after key shut off and kill switch engaged...
Post by: Howie on November 28, 2018, 05:44:42 PM
Quote from: Luis C Reyes on November 28, 2018, 01:07:48 PM
with quality not always improving, that is something to think about.
I did not measure the voltage drop on the solenoid when it was installed.
Maybe I will just use it and measure the V drop. I have heard/reaad 1v drop is expected across the solenoid.

1 volt would be excessive for the whole circuit.  Typical drop would be .2 volts.  Ducati has no official spec AFAIK.