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And the Dropbox has been updated accordingly, as in Dario's text and pics added to the document on cold start issue.
cold start update
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UPDATE!!!! IT WORKED ON MY BIKE, NO MORE COLD START ISSUE (TESTED AT 4°C OR 39°F)!!!!!!!!!!!!!!!
The diode I used is a 1N5401 (it was the one that I had available)
I'm very happy right now, the bike started with no hesitation!.
This modification is very recommended. That flyback voltage it was really messing with the Power Commander. The diode suppressed that spike.
This forum is amazing! Thank you to all the contributors!
The diode I used is a 1N5401 (it was the one that I had available)
I'm very happy right now, the bike started with no hesitation!.
This modification is very recommended. That flyback voltage it was really messing with the Power Commander. The diode suppressed that spike.
This forum is amazing! Thank you to all the contributors!
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Yes sir, It works!!
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Yeah I'm still geeking out about this whole diode shunt thing. Very interesting subject, flyback voltage. I tried talking to dynajet about this but got no reply, their loss.
I'm absolutely stoked that Nealio and Dario could replicate the diode shunt/cold start fix. Well done fella's. I look forward to more people trying this. Three positive results is excellent.
Thanks to Mcromo for the Dropbox work.
And a big thanks to Rob, for it all.
Still cannot wipe the shit eating grin off my face everytime I start my bike.
I'm absolutely stoked that Nealio and Dario could replicate the diode shunt/cold start fix. Well done fella's. I look forward to more people trying this. Three positive results is excellent.
Thanks to Mcromo for the Dropbox work.
And a big thanks to Rob, for it all.
Still cannot wipe the shit eating grin off my face everytime I start my bike.
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More testing :
Last night my bike was tested at -6°C or 21.2°F. The bike started right away. Before the shunt diode fix, when lower than 7°C or 44.6°F I had a hard time trying to fire her up.
So this result is conclusive, finally a real solution for the cold start issue on bikes with the power commander installed.
Also with or without power commander, the transient (flyback voltage) is being generated every time that the start button is pressed, so maybe it will affect another electronics parts of the bike. For example my bike had a defective speed sensor (I replaced it a couple of weeks ago) and now I`m thinking that was affected by that transient at some point.
So it is a recommended modification for all 919.
Last night my bike was tested at -6°C or 21.2°F. The bike started right away. Before the shunt diode fix, when lower than 7°C or 44.6°F I had a hard time trying to fire her up.
So this result is conclusive, finally a real solution for the cold start issue on bikes with the power commander installed.
Also with or without power commander, the transient (flyback voltage) is being generated every time that the start button is pressed, so maybe it will affect another electronics parts of the bike. For example my bike had a defective speed sensor (I replaced it a couple of weeks ago) and now I`m thinking that was affected by that transient at some point.
So it is a recommended modification for all 919.
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-6 degrees is a very cold start! Well done mate. Great result.
I agree the negative voltage spike is better run to ground than through our bikes electrical system.
Dario I would like to make a diode shunt harness similar to yours. I've no experience doing this type of electrical work so need some advice. I've ordered some pcb board. How is diode and wiring soldered on? You don't have a pic of the reverse side of your diode soldered up? Also conformal coating. Would silicon glue be OK?
Thankyou.
I agree the negative voltage spike is better run to ground than through our bikes electrical system.
Dario I would like to make a diode shunt harness similar to yours. I've no experience doing this type of electrical work so need some advice. I've ordered some pcb board. How is diode and wiring soldered on? You don't have a pic of the reverse side of your diode soldered up? Also conformal coating. Would silicon glue be OK?
Thankyou.
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I will make a new one and will take pictures (step by step).
For now this:
The conformal coating is a dielectric coating, that protect the electronics components against moisture or contaminants. Is kind of a clear coat, usually you apply the coating to all the components, pcb and wires. If you don`t have a specific electronics conformal coating I think you can use a transparent nail enamel. You have to clean the assembly very well before applying the coating (cleaning with isopropyl alcohol is ok).
For the diode, you have to form the leads to be able to fit the part in to the little holes of the PCB. When forming the leads, try to not bent them to close to the body (cause you will cause stress and the part will crack eventually), then insert the part in the pcb, then solder the part on the bottom side, then cut the leads. Now, prepare the wires (strip the insulation), thin the wire using your iron and some solder, then solder the wire to the pcb and the lead. You can be generous with the amount of solder here. Do the same with the other lead, clean the flux residue with isopropyl alcohol, you can stake the wires to the PCB using some silicone glue, them apply the coating, then use some shrink tube to cover the assembly and you are ready to go!
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Do thy mod and ye shunt have a problem :beerpopcorn:
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Was actually worried about this since I haven't started the bike since December 6th and we've had some pretty cold nights constantly fluctuating between -5c and 5c.
Got my seat yesterday and turned the bike on for the first time. 1s push and it fired up no problem. Perhaps at a lower idle but she fired up no problem
glad I don't have this
Got my seat yesterday and turned the bike on for the first time. 1s push and it fired up no problem. Perhaps at a lower idle but she fired up no problem
glad I don't have this
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Over time though, you may develop this hard start (when outside temp is cold, not necessarily the bike) issue associated with the PCIII. I say this because the fly-back voltage was never a constant for me. If the bikes sat for a long period of time it seemed to start immediately with low outside temps. But on the day after day riding and COLD morning starts, the issue got more predominant.Was actually worried about this since I haven't started the bike since December 6th and we've had some pretty cold nights constantly fluctuating between -5c and 5c.
Got my seat yesterday and turned the bike on for the first time. 1s push and it fired up no problem. Perhaps at a lower idle but she fired up no problem
I cant say this is true for all bikes, as one of my two 919's did this more than the other. The other bikes I performed this on- the owners didn't notice if the condition was worse or not if the bike sat for long periods of time or ridden daily.
Just keep an eye on it.
My '08 990 Super Duke has a cold start issue, that sounds very similar to what you guys have going on.
I used to be able to get around the problem by keeping the Shorai on the Battery Tender. But lately, that doesn't work. Not sure that Iknow enough, to figure this out on my own. I'm going to give it some thought.
I used to be able to get around the problem by keeping the Shorai on the Battery Tender. But lately, that doesn't work. Not sure that Iknow enough, to figure this out on my own. I'm going to give it some thought.
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That is correct.
Cold start issue. Bike will fire up staight away but engine stalls the moment the starter button is released as this is when the negative voltage spike is generated by the deactivating starter relay.
OR the shit hits the fan when you take your finger OFF.
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