Stalling, electrical problems

[barrkel]

For the past couple of weeks, I've been having a problem with my 2012 SH300 scooter.

Occasionally, while riding down the road, the engine would skip a beat or two, like the spark not firing, feeling a bit like it was just running out of fuel. At the same time, the dash would go crazy: various status lights go on and off, the gauges go back to zero then start their turn-on dance, and the LCD display turn off and on.

Sometimes, the engine problem indicator light would start flashing code 12 - one long blink, two short blinks - which the manual indicates is a fuel injection problem. When this happens, the ECU turns the engine off, and you have no choice but to drift to the side of the road, reset the ignition with the key, and restart while holding in the brake - no moving restarts possible. Makes the bike dicey to ride in traffic. But other days it would be perfectly fine.

This bike has just recently been returned from insurance-approved repairers from an accident I was in.

Initially I thought it was a loose wire, possibly from the accident, and I stripped most of the fairings off and checked the state of every wire and connection I could find - I poked at them all (save the HT between ignition coil and spark plug) while the engine was idling, and no hiccups. I changed the spark plug, in case the engine was having a hard time sparking - it was also soon due for a change. And then problem seemed to go away - for a day.

Now it's back with a vengeance. Cuts out at the beginning of most journeys, and this evening it was really hard to get started. Earlier today even the ABS light started blinking as it failed its power on self test - I could hear it weakly whirring away when the ignition was turned on.

Just earlier this night, I finally had the bright idea of wiring up a voltmeter to the battery. Read 12.6 volts or so with ignition off; with the ignition on, 12.3 volts and dropping about 0.1V a second (the headlight is fully lit with the engine off). And once started, on the centrestand, when powering up to ~10% throttle and snapping back to 0, sudden drops to 5 or 6V were apparent - and that's exactly when a few missed sparks happened.

I figure it's a dodgy winding in the stator, and for whatever reason, some engine revs make it worse than others. And depending on how healthy it's been for the past while, the battery is either well charged, or staggering on its last legs. So the symptoms vary from day to day.

Has anyone else seen big voltage drops like this (almost like the voltage is reversed in the charging circuitry momentarily)? Or is it more likely to be the reg/rec? Or something else entirely (possibly ignition coil)?

I'll be testing the stator reg/rec connector for connectedness and voltage tomorrow if I get the weather for it.

Also not sure if I should be chasing dealer or insurance for repairs. Will probably be taking it to the dealer with diagnosis, and if they don't want to do warranty, hopefully they'll give me an independent opinion I can take to the insurance.
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Bikes: S1000R, SH350; Exes: Vity 125, PS125, YBR125, ER6f, VFR800, Brutale 920, CB600F, SH300x4
Best road ever ridden: www.youtube.com/watch?v=s2MhNxUEYtQ

[Fizzer Thou]

I have absolutely no idea about your particular machine,but the common connection from your description sounds like a bad earth.This is easily checked by placing the multimeter between the negative post of the battery and any point on the engine or frame that is being used for an earth return.There should be few if any ohms of resistance.A reading of zero ohms is the norm.Quite often there is some corrosion between a main cable and the engine or frame.Quite often an extra earth strap from the coil bracket to a good frame connection works well.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[unitynotsocri...]

i've read about many scoots using a fuel pre heater/thermostat that also acts as a fuel tap.........heres a picky.

you might need the fuel system servicing,if it has a cv type carb....with a flat top.....then the rubber diapghram might be having hiccups.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

[Timmeh]

+1 for broken earth
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GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[barrkel]

I've just checked the connectivity between negative terminal and steel bolts on the engine block - 0.1 ohms with engine off, ~2 ohms with engine on. The block itself is coated aluminium, with a fair amount of resistance.

I also did the same test I did before, checking the voltage while revving, and now it doesn't seem to drop, which is puzzling - makes me wonder if my probes had solid connection to the battery on Tuesday. It doesn't rise either, solid 14.6V throughout, but the engine still spluttering to a halt. There's definitely something electrical wrong though, as the ABS self test is weaker and weaker each time the ignition is switched on.

I've booked it in with a dealer, and have taken the battery out and put it on a charger, hoping that will increase the probability of making it to the dealer. Warranty should sort it.

Thanks for the help folks. It might be a loose wire after all.
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Bikes: S1000R, SH350; Exes: Vity 125, PS125, YBR125, ER6f, VFR800, Brutale 920, CB600F, SH300x4
Best road ever ridden: www.youtube.com/watch?v=s2MhNxUEYtQ

[barrkel]

Turns out this was a dodgy starter relay - intermittent failure when vibrating. Took the mechanic at the dealer hours to find it, but sorted under warranty.
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Bikes: S1000R, SH350; Exes: Vity 125, PS125, YBR125, ER6f, VFR800, Brutale 920, CB600F, SH300x4
Best road ever ridden: www.youtube.com/watch?v=s2MhNxUEYtQ