Side stand sensor failure

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bambadoo
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Side stand sensor failure

Post by bambadoo » Thu Jul 05, 2018 1:48 pm

Hi
I know its an issue but this time it happened me.
On a small "boys" vacation I got a distress call saying my son (3.5 years) was hurt and needed surgery.
I had to hurry up and head home. Had approx 300km before I could see him. After about 200km the bike died out of the blue. This was at night and I soon discovered that it had to be the side stand sensor. It would start in neutral but as soon as I shifted gear it stopp.
Called the insurance, got hold of a "towing truch" and had to hire a rental car for the remaining of the trip.
Surgery went fint but he might loose one toe.

I had to get the bike with a hanger yesterday.

Made a "bypass" sensor yesterday consisting of 2 1.5kohms resistors.
Fitted it and it starts. It also runs in all gears
However - I can only start it in neutral. Not in any gear with clutch in.

Is that normal behaviour with such a bypass dongle?

Sincerely
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ktm.jpg
ktm2.jpg
ktm3.jpg

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Re: Side stand sensor failure

Post by bambadoo » Mon Jul 09, 2018 8:14 am

However - I can only start it in neutral. Not in any gear with clutch in.

Is that normal behaviour with such a bypass dongle?
Anyone got experience with this?

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Re: Side stand sensor failure

Post by Magic Wand » Mon Jul 09, 2018 10:00 am

Hi 'bambadoo'!

Sorry, I have no experience from a bypass dongle at all. Is it a problem that you need to use Neutral when starting the engine? I always do that... No reason to start it with gear in position.

/M
-

Hej hej!
Jag har ingen erfarenhet av egentillverkad bypass till sidstödssensorn.
Däremot gick den sönder på min SMt när jag körde i Norge 2015.
Via internet hittade jag denna sida och tips om att kapa en kabel (grönt hölje) och jorda den i ramen på motorcykeln. Då fungerade det, men Neutrallampan lyste ständigt. Det gjorde mig inte så mycket, jag vet ändå alltid vilken växel som är i.
Bytte sidstödssensor när jag kom hem samt skarvade kabeln som jag hade klippt av, med en skarvhylsa och tätade med silicon om jag minns riktigt.

/M

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Re: Side stand sensor failure

Post by limeyduffa » Mon Jul 09, 2018 10:47 am

What causes this failure ?. I assume it's a hall effect sensor ?

I think it's an important safety feature. There was a big accident a few years ago in the hills near my parents place. I Harley Davidson side stand collapsed when the rider was in a corner. The high side killed him (His sidestand put a divot in the bitumen). My (double) spring broke on my 990 SD at a supermarket. If I had been riding, and it went down in a corner, the result could've been catastrophic like the poor Harley rider. If mine fails, I will be replacing it.

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Re: Side stand sensor failure

Post by Magic Wand » Mon Jul 09, 2018 8:16 pm

Hi 'limey'

Don't know if the hall effect sensor is the same as a side stand sensor. Do you talk about the magnetic inside the unit?

Tragical story about the side stand that came down and killed the HD dude... :/
The stand came down in a right hand curve and when next left hand curve... bad.
(But that accident was of course not caused by a side stand sensor failure)

/M

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Re: Side stand sensor failure

Post by limeyduffa » Tue Jul 10, 2018 10:27 am

Hi M

It's either going to be a reed switch (mechanical), or a Hall Effect sensor (solid state). If it's the latter, it should be very reliable.

Regarding your last point, my understanding of the side stand sensor is if the stand goes down when bike is in gear, engine is cut ?. If that is the case, the bike will roll to a halt ("safed") if the stand goes down during riding.

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Re: Side stand sensor failure

Post by eagle_awd » Wed Jul 11, 2018 12:05 am

I have KTM bypass dongle and starts in any gear...

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Re: Side stand sensor failure

Post by bambadoo » Wed Jul 11, 2018 10:18 am

Ok thanks. Thats strange. How is it built up?
I am aware of all the things that can happen with defunct sidestand.

I have new sensor on order and will mount it as soon as it arrive. Then I will put my "bypass" under the seat in case of an emergency :)

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Re: Side stand sensor failure

Post by Magic Wand » Wed Jul 11, 2018 11:44 am

limeyduffa wrote:
Tue Jul 10, 2018 10:27 am
Hi M

It's either going to be a reed switch (mechanical), or a Hall Effect sensor (solid state). If it's the latter, it should be very reliable.

Regarding your last point, my understanding of the side stand sensor is if the stand goes down when bike is in gear, engine is cut ?. If that is the case, the bike will roll to a halt ("safed") if the stand goes down during riding.
-

Ok, yes it should be reliable.

Yes, engine 'dies' if the side stand goes down, for any reason.

/M

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Re: Side stand sensor failure

Post by limeyduffa » Wed Jul 11, 2018 3:58 pm

My parts arrived today, so I have been assembling my bike tonight

Confirmed: side stand sensor is a reed switch. The touch plate on the side stand is magnetic. That explains the high failure rate.

I might have to make myself a bypass too in case it fails. It's only a matter of time :)

J

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Re: Side stand sensor failure

Post by limeyduffa » Thu Jul 12, 2018 1:15 am

bambadoo

Could you try using a small magnet taped/wired to your faulty sensor to see if that works ?. Just thinking of a simple solution if their is a failure.

J

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Re: Side stand sensor failure

Post by bambadoo » Thu Jul 12, 2018 8:55 am

I tried this when I got the problem :
https://www.youtube.com/watch?v=P0lTF4nilDY

It did not work for me. I guess it is the sensor itself or breakage in the cable.

I will get new parts today.

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Re: Side stand sensor failure

Post by limeyduffa » Thu Jul 12, 2018 10:38 am

Ok, thanks for info. I'll make the mod as a contingency plan :)

BTW: I mentioned my 990 SD spring breaking at a shopping centre one 40 degree day (not the most convenient time for that to happen). With my SMT a few years ago, I was camping in a remote area. About a day's journey away from home. When I got home, I gave the chain a clean and discovered the side stand bolt was holding by a thread :o . When I saw that, I was like... "f*ing hell !"
07_side_stand_bolt_half_out.jpg

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Re: Side stand sensor failure

Post by eagle_awd » Thu Jul 12, 2018 2:19 pm

Can't really tell what's inside. I got it as preventive, because these sensors do go bad and did not wanna be left stranded on the side of the road, especially on the longer trips. And bypass was cheaper then new sensor :D
Got used to checking even three times before I leave, to make sure stand is up :)

Image

bambadoo wrote:
Wed Jul 11, 2018 10:18 am
Ok thanks. Thats strange. How is it built up?
I am aware of all the things that can happen with defunct sidestand.

I have new sensor on order and will mount it as soon as it arrive. Then I will put my "bypass" under the seat in case of an emergency :)

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Re: Side stand sensor failure

Post by limeyduffa » Sun Sep 23, 2018 1:33 pm

Hi bambadoo

Last month, I followed up your work on the side stand sensor and measured the voltages and currents of my side stand sensor in order to understand the problem.
01_measure_11AUG18.jpg
02_measure_11AUG18.jpg
I've derived an equivalent circuit. The sensor + ECU is equivalent to this circuit: Three resistors:
03_cct_equiv_11AUG18.jpg
Unfortunately, the 10 kilo Ohm (10k) resistor that represents the side stand sensor and whatever is in the ECU is unknown.

I finally got around to building your dongle today, with slightly different resistor values to see how the bias of the potential divider would change the voltage of the pink wire.
04_dongle_resistor_23SEP18.jpg
Your potential divider has two 1.5k resistors (symmetrical). I made my divider slightly asymmetrical by 120R (1.5k & 1.5k + 120R). I interchanged divider so that the divider's voltage would provide a voltage source of either 2.4V or 2.6V for the pink wire. The result is, no matter what configuration (2.4V or 2.6V), the voltage of the pink wire is 3.1V. The draw of the pink wire is pulling up the voltage of the divider. So rather than muck around with resistor values, I am going to make another dongle with a constant current source of 1.2mA to replicate the 1.2mA draw I found in my measurement. Watch this space on that. I think that might be a better approach.

To you results, mine match yours. With my dummy load + stand down, I need to put the bike in neutral in order to start bike. With sidestand sensor connected + stand down, bike will start in gear.

PS/ Sensor is a hall effect sensor. I was wrong on my first reply.

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Re: Side stand sensor failure

Post by eagle_awd » Mon Sep 24, 2018 2:11 pm

Let me know if I can measure my dongle somehow to help you out.

I'm electronics antitalent, but can measure basic things...I think :)

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Re: Side stand sensor failure

Post by limeyduffa » Tue Sep 25, 2018 2:47 pm

Yes please eagle_awd. If you could also measure the current flow into the pink wire that would be good too.

Just to follow up my last post, here are my ideas below.

The top circuit is a temperature compensated constant current source using a small LM334 IC, a diode and 2 resistors. A printed circuit board won't be needed. Just solder the components together. This circuit is out of the LM334 datasheet. I just used their formula to compute 1.1mA (milli Amp) (which approximates my measured 1.2mA current that flows into pink wire)
05_CC_cct_pot_ideas_25SEP18.jpg
Now, I can tell, that this is too complicated for most people :lol:, so, a simpler approach is a 3 resistor circuit. First you start with two 560 Ohm resistors and a variable potentiometer. I found thecurrent draw going into the pink wire is 1.2mA (on my bike). This is caused by an equivalent 10k (kilo Ohm) load that is equivalent of the sensor plus what ever is in the ECU sensing the pink wire (as mentioned in my last post, the individual resistor values of sensor and ECU are not known). The idea of the potentiometer is you set it to various resistances until you get the value that works (or measure the current going into the pink wire until it is equal to 1.2mA). Once this pott value is worked out, replace pott with a fixed resistor.

The advantage of the constant current circuit is it is thermally compensated. The resistor circuit isn't. Thermal compensation can be added to this circuit, but then circuit becomes complicated.

I'm busy for the next few months with other stuff. When I get around to it, I'll build both of these dongles. Watch this space :)

BTW: I sourced the connectors and pins (with the help of some autolect gurus on netrider) from here if anyone is interested in making a dongle from scratch:

https://jaydeeautocables.com.au/product ... -terminals
https://jaydeeautocables.com.au/product ... 4335397441

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