Bike electrical issue

Hey guys. Having an issue with my bike. It's happened a few times now where can be riding along and then there is a complete loss of power and then it picks up again. On other occasions there is a loss of power and then the engine cuts out and won't start again for a few minutes. Does this sound like it could be the crank sensor? Any ideas guys?

Does it turn over when you try to restart it or is it dead?

try to check easy things first like the bike stand is it telling the bike its down? easy to check, the kill switch have a look at that easy to get at to have a look at it then start with the more tricky stuff probably not much help but you'll get plenty of other idea's from the guys on the site

This is one of those tricky problems where it would be easier to find if the bike stopped completely , have a look at the battery connections to make sure they are tight and not corroded and all the wiring in that area is secure, have you fitted any extras? i,e spotlights that may shorting out, failing that it is a case of checking through the bike for faulty connections or wiring, sorry I can,t offer any more advice but these are bad problems to sort out, good luck with the fault finding, regards Doc Cox.

Bad 'Earth' on the power commander?

Vtwin..it won't turn over. 
One of the guys from our club has had it apart. Gone through the wiring, kill switch and all that and everything was fine. As for the Power Commander I'll ask him if he's checked that. Cheers.

Ignition switch. Kill switch or side stand switch would be favourite!!

v-twin wrote:

Ignition switch. Kill switch or side stand switch would be favourite!!

Non of these will cause a complete lack of power.

If the ignition switch is not making contact properly it will die and then pickup again when the contact is made, same as the kill switch and side stand switch etc, my old bike had a dodgy side stand switch and it would loose power and then when I hit a bump off it would go again.
It sounds electrical to me with an intermittent wiring/switch problem.

v-twin wrote:

If the ignition switch is not making contact properly it will die and then pickup again when the contact is made, same as the kill switch and side stand switch etc, my old bike had a dodgy side stand switch and it would loose power and then when I hit a bump off it would go again.
It sounds electrical to me with an intermittent wiring/switch problem.

I agree Andrew   When I first read the post I thought it was lack of power from the engine not loss of electrics, more information would help Rattler, does everything go off? clock lights? lights an stuff? as in a complete electrical failure? or just the engine won't start? 

I thought it was electrical because he said the following:

there is a complete loss of power and then it picks up again. On other occasions there is a loss of power and then the engine cuts out and won't start again

Ken1964 wrote:

I thought it was electrical because he said the following:

there is a complete loss of power and then it picks up again. On other occasions there is a loss of power and then the engine cuts out and won't start again

Yeah Ken, I was confused as well 

The thread is in the electrical section.

If it is only the motor that die i would propose as earlier, check sidestand, kill switch and ignitionkey for faulty wires and/or bad connection.

If the bike loose all electrics i would start checking fuses and the slots that holds the main fuse. Might be bad contact there that makes the power to cut.

If it always starts after a period of time that seems to be about the same lenght everytime. And after a similar time of running i would suggest that it is some component that gets to hot and therefor cuts the power and start working again when it cools down. Like a thermo-contact on an electrical motor. Dont know if there is something like that mounted on the bike.

Hope to get some more info on this issue so we might be able to narrow it down abit. 

Good luck with the fault finding.

Cheers guys. I'm about to go out and test the side stand switch to start with.

It's not a complete electrical failure and it's not when it gets warm. I've just had it running and after maybe 15 seconds the engine cut out. The lights are still on and the display but I've noticed the fuel pump primes itself again and randomly primes itself again while the ignition is on sometimes a few times in a row.

Sounds like a break or short in the circuit somewhere Rattler, the symptoms would lead to 'kill switch' and 'side stand switch' but if you've checked them and they're fine? it could be a chaff in the wires or connections going to them also?

Check the wires where they go around the side of the fuse box bracket on the lower left hand side  ,mine were almost worn through causing all sorts of electrical tomfoolery ..

Any findings yet Rattler?

No mate. It's been suggested by one of the guys in our club to test the tilt/drop switch by bridging it. Gonna have a look again on Sunday.
Any ideas where it is?

No idea mate? I was under the impression it was in the ECU and that was just for reducing power in the event of wheelie's? more of a sport bike thing?

If it is just the motor electricity that dies i would suggest you disconnect/ re-route the cables for the side stand switch and kill switch to strat with.
I would do them one at the time to be able to isolate the fault.
Start with the sidestand switch thats the easiest to get to.
My girlfriend had an issue on her kawasaki VN800, when she was trying to start after beeing parked the bike died when she was in gear and had the clutch on the way up.  and after a few tries to drive away it worked.
That was a really dirty side stand sensor. the mechanics in the sensor/spring didnt move fast enough after side stand was raised so it gave a faulty signal.

Check the small easy things first.

We worked on it today for a few hours. Bridged and checked voltage/ohms on side stand switch, crank sensor and reg rec all fine. Checked the battery and at idle its around 14v but at higher rpm maybe around 5000 rpm it drops to around 2v. Maybe a battery problem or sonething I've added is pulling too much? Power Commander, alarm or TRE.

I have a volt meter on my bike and 14V sounds about the same as mine.

Drops to around 2V at at idle?

Surely 2v is a typo ? ...... Do you not mean 12v ?

No not a typo. At idle its at around 14v. As you twist the throttle it rapidly drops to 2v at an estimate of 5000 rpm.

It's been suggested it could be the Stator. Here's the video of the battery voltage. It didn't go down to 2v on.this occasion but as you can see, it goes down to 4v.

https://youtu.be/Gcn6YXoUq9k

This could be of use:

http://www.suzuki-katana.com/pdf/chargingfault.pdf

The 800 has a three state charging system, meaning it will put out more at different rpm's. The thing is that doesn't explain the 2v thing, as the battery is 12v on it's own. Where did you get the voltage from?

The voltage was directly from the battery. We are starting to thing possible reg rec or stator maybe. There definetly is no tilt/drop switch on the bike.

Check the earth wire/grounding from the reg/rec to the frame as it will give all sorts of dodgy readings if it is not a good connection. From memory, the stator gives about 70v ac across each phase at 5000k, watch you fingers as it will hurt. Good place to start is with the bike off put the multimeter on the 200 ohm range and measure the resistance across a pair of the stator windings, should be a few ohms, compare the readings against the other pairs, they should be the same also double check the connector where the stator wires plug into the reg/rec as one could have burnt out, again would give some odd results. My money is on either a dodgy earth or reg/rec blown. Just try one thing at a time and take notes of what you did and the results you got as it will all become a blur if you do not.

Rattler wrote:

Not not a typo. At idle its at around 14v. As you twist the throttle it rapidly drops to 2v at an estimate of 5000 rpm.

The Voltage does change as you go through the rev range, as Crash says, with a variable stage charging system. I actually have a numeric LED voltage display scale on my bike and your tickover voltage is correct at around 14 volts. As for your voltage meter, reading 2 volts from the batter at about 5000 rpm, that is not correct. It would not be possible to get that reading from a 12 volt battery that has started the bike. The battery requires at lest 12.2/12.3 volts to start the bike, that voltage will not disappear to give two so drastically different readings. Sorry but that reading can only be got by a crap volt meter.

Well we checked it again today and it was dropping to that. I've swapped the battery and it's sorted. Ran smoothly and didn't cut out And the voltmeter tested it at between 13 and 14v when rpm increased.

Hi Rattler, good to see you've sorted the problem , if the problem reoccurs then test the rectifier.

stingray wrote:

Hi Rattler, good to see you've sorted the problem , if the problem reoccurs then test the rectifier.

I agree.

To that .... & glad things are now 'sorted' for you.

The rectifier tested ok yesterday. Hopefully it's sorted now.

Fingers crossed.

Damn things done it again. I'm wondering if it may be the fuel pump as it did the loss of engine power and then it picked up again. It was a bit later that it cut out. It wouldn't start again for a few minutes but then I heard the fuel pump prime at then it fired up.
Also, after it had cut out but wouldn't start the gear indicator on the TRE wasn't illuminated like it should have been.

Hi Rattler I know it is a different bike but a common fault on Honda Deauville is the rectifier, or wires associated with it, and gives the same problems you are experiencing. Hope you sort it, as it is one of the most frustrating problems to have. Also I know it sounds daft but check your fuel pump connections under the tank in case it is a loose or broken wire, for as you said you heard the fuel pump fire up and then it started. Good luck.

Yeah got a few things lined up to look at next including fuel pump and rectifier. Cheers Alfie.

alfie92 wrote:

Hi Rattler I know it is a different bike but a common fault on Honda Deauville is the rectifier,

 Same with the R6, bad connections and earths too, check connectors for arcing and burnt plastic connectors.

Will do guys cheers. We were talking about it last night and wondering if it could possibly be a fault with the Power Commander?

If you have concerns with the power commander, take it off for a while.
I agree to check the rectifier for a bad connection. Always clean up any connection and give them a smear with Vaseline before refitting them, saves problems later.
The regulator/rectifier had a recall some years ago but I can't remember which years were involved.
The bit that has me thinking is that you say the following

Rattler wrote:

It wouldn't start again for a few minutes but then I heard the fuel pump prime at then it fired up.

Again as the guys have said, check the side stand switch. I know you said you have bridged and checked it for voltage. That will only tell you something if the the intermittent fault you have is at that moment currently happening. Keep it simple and don't check it for faults, disconnect/bypass the side stand completely & then see how you get on.

Cheers Dave. We are working on it tomorrow so will look at the reg rec again.

Thr reg reg recall looks like it was 07-10 so doesn't include mine.

After a lot more work yesterday we think we have found the issue. I have ordered a new fuel pump relay so hopefully that sorts it out.

Good luck Rattler Sir, it will be interesting to know if this is the culprit.

It wasn't the relay. We are thinking now it may be a fault with the alarm. So that's the next thing to look at.

I know it's been said before but have you bypassed the side stand switch?