No 12v on bike

Newt232 · 10-07-2021, 11:59 PM

Hi all,
I'm not sure what happened but I recently took my bike for a spin with a strangely dead battery. I soon realized that I had no signal lights, and then pulled over to find that none of the lights were working. Investigating further, there was no 12VDC to run anything on the bike.

The bike is running, and I've been able to note that while running there is less than 1vdc going to the spark coil, and the harness coming off the engine to the shut off switch is up around 80VDC. The 12V regulator has nothing close to 1VDC on it, nevermind 12VDC, and the CDI unit has that full 80VDC in but again less than 1VDC out. Does this indicate a faulty CDI unit or a faulty wiring harness that isn't supplying voltage from the alternator to the 12V regulator? Perhaps I'm missing something and perhaps the stator itself went bad. I will start it up tomorrow and get the voltage between the yellow / white wire and ground. That said, seeing 80V into the CDI isn't to be expected is it? I'm amazed it runs.

I ordered the complete wiring kit (harness, stator, CDI, handlebar controls...) and will probably proceed first with installing the stator, then perhaps the harness. Also reference this page when doing more electrical testing:

http://www.chinariders.net/showthread.php?t=13934

braindead0 · 10-08-2021, 10:31 AM

The 1vdc reading on the spark coil is likely incorrect, the voltage is cycling at a high rate of speed so you're meter will not get a steady reading.

If you're seeing 80VDC your regulator is shot.. I'm surprised those voltages didn't fry the CDI...

You might want to verify your meter is in proper working condition.

franque · 10-08-2021, 02:25 PM

This might have an AC CDI, in which case you're measuring the wrong thing anyway.

Newt232 · 10-08-2021, 07:10 PM

Quote:

Originally Posted by franque

This might have an AC CDI, in which case you're measuring the wrong thing anyway.

This is measured using a autoranging Fluke meter. I checked the AC component but there was nothing worthy of note either.

duck9191 · 10-09-2021, 03:06 PM

the cdi and coil are likely all ac but it depends on the bike. The only dc would be the output side of the regulator rectifier to the battery and all the accessories. The yellow wires from the stator should be reading ac voltage. if they don't take an ohm reading from winding to winding and from each winding to the case to see if any are broken or shorted.

Newt232 · 10-13-2021, 06:21 PM

Quote:

Originally Posted by duck9191

the cdi and coil are likely all ac but it depends on the bike. The only dc would be the output side of the regulator rectifier to the battery and all the accessories. The yellow wires from the stator should be reading ac voltage. if they don't take an ohm reading from winding to winding and from each winding to the case to see if any are broken or shorted.

I got the bike running again, and between ground and the three poles of the stator I measured between 50-80VAC; but less than 1VAC coming out the other end of the wiring harness to the CDI and the voltage regulator, so I'm pretty sure it's the wiring harness. I bought a generic complete wiring kit:

https://www.amazon.com/dp/B07PMGVJNG

I observed that one of the wires leading out of the main harness to the regulator has been completely cut; so that's a good clue. I may swap out the throttle/signal/starter unit while I'm at it, as I'd bypassed the relay and went with a push-button down on the left of the engine a while ago when the starter switch plastic broke off in the woods (d'oh!). I was tempted to try the adjustable CDI units to advance/retard the spark timing but there are mixed reviews on those. I think my motor has a rev limter at 9800 rpm or so and wonder if this would increase top-end power or an unnecessary mod:
https://www.amazon.com/Ignition-Alum.../dp/B07P9QXQLX

I'll try to switch the harness and see what happens.

mototech77 · 10-13-2021, 11:43 PM

Sounds like you’re on the right track with the wiring. I would be very cautious about trying to rev the engine beyond the designed redline, though. The forces generated on reciprocating parts can reach a destructive level, and chances are you are going outside the peak HP curve anyways unless you are upgrading the cam, etc. more RPM doesn’t always equal more HP.

Newt232 · 10-14-2021, 09:13 AM

Quote:

Originally Posted by mototech77

Sounds like you’re on the right track with the wiring. I would be very cautious about trying to rev the engine beyond the designed redline, though. The forces generated on reciprocating parts can reach a destructive level, and chances are you are going outside the peak HP curve anyways unless you are upgrading the cam, etc. more RPM doesn’t always equal more HP.

Oh absolutely, I don't like getting up towards the redline as the vibrations seem to get harsher and I can get circulation issues if I have it up at those high rpm's for long time. I'm more curious about the effect of variable spark timing than I am in the rev limiter. Could you use a custom EFI to take better advantage of a different fuel and get a more efficient burn? I saw a funky three lobed spark plug that came with one of them, very intriguing. I'm currently stopping every 100km to refuel and it's a bit of a PITA. I'm actually considering moving to a 650 as my buddy has one and I keep getting dropped when we ride, something like a DR. Trying my level best to squeeze all the horses I can from this thing first though!

mototech77 · 10-14-2021, 12:06 PM

Quote:

Originally Posted by Newt232

Oh absolutely, I don't like getting up towards the redline as the vibrations seem to get harsher and I can get circulation issues if I have it up at those high rpm's for long time. I'm more curious about the effect of variable spark timing than I am in the rev limiter. Could you use a custom EFI to take better advantage of a different fuel and get a more efficient burn? I saw a funky three lobed spark plug that came with one of them, very intriguing. I'm currently stopping every 100km to refuel and it's a bit of a PITA. I'm actually considering moving to a 650 as my buddy has one and I keep getting dropped when we ride, something like a DR. Trying my level best to squeeze all the horses I can from this thing first though!

I agree. I’m not sure what bike you have but I do like the sound of being able to maximize the tuning on mine. If you have an EFI bike, some have mentioned using HUD ECU Hacker, but updating ECU tune is out of my realm at least so far. The EFI stuff can be finicky if you mess with the exhaust and intake box, etc. JerryHawk250 and Megadan both have posted some good info regarding mechanical mods. JerryHawk250 has a YouTube channel where he showed installing a 4 degree offset flywheel pin to advance the timing on one of his bikes. I think for these EFI bikes, being able to get the fuel map improved would be very helpful, but outside of getting a legitimate tune done, the only other option I’ve found is a piggy back device that cost $250 and seems a bit gimmicky. It sure is tempting though. Gearing change could help you depending on what kind of riding you do. I don’t go off-road much, so I swapped out my rear sprocket and I am able to get to 65mph (70 if it is level and not too hot out). It still does fine at lower speeds, but might not be the best for technical trails. I will enjoy this bike for some time while I improve my riding skills, then I will probably get something a little bigger later on.

Newt232 · 11-15-2021, 07:58 PM

So I looked under the seat and of the four wires coming off the stator, one had broken about an inch from where it plugs into the regulator. I left the harness on the bike, and just resoldered the thing together where it was at. Voila! 13.something at the battery terminals!

I may be selling this one now, I've got a lot on my plate and probably shouldn't be on anything with two wheels, but I'll miss this little guy a lot, that's for sure.

10-07-2021, 11:59 PM	#1
Newt232 Join Date: Oct 2018 Posts: 25	No 12v on bike Hi all, I'm not sure what happened but I recently took my bike for a spin with a strangely dead battery. I soon realized that I had no signal lights, and then pulled over to find that none of the lights were working. Investigating further, there was no 12VDC to run anything on the bike. The bike is running, and I've been able to note that while running there is less than 1vdc going to the spark coil, and the harness coming off the engine to the shut off switch is up around 80VDC. The 12V regulator has nothing close to 1VDC on it, nevermind 12VDC, and the CDI unit has that full 80VDC in but again less than 1VDC out. Does this indicate a faulty CDI unit or a faulty wiring harness that isn't supplying voltage from the alternator to the 12V regulator? Perhaps I'm missing something and perhaps the stator itself went bad. I will start it up tomorrow and get the voltage between the yellow / white wire and ground. That said, seeing 80V into the CDI isn't to be expected is it? I'm amazed it runs. I ordered the complete wiring kit (harness, stator, CDI, handlebar controls...) and will probably proceed first with installing the stator, then perhaps the harness. Also reference this page when doing more electrical testing: http://www.chinariders.net/showthread.php?t=13934
	0

10-09-2021, 03:06 PM	#5
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	the cdi and coil are likely all ac but it depends on the bike. The only dc would be the output side of the regulator rectifier to the battery and all the accessories. The yellow wires from the stator should be reading ac voltage. if they don't take an ohm reading from winding to winding and from each winding to the case to see if any are broken or shorted. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
	0

10-13-2021, 11:43 PM	#7
mototech77 Join Date: May 2021 Location: Central Florida Posts: 80	Sounds like you’re on the right track with the wiring. I would be very cautious about trying to rev the engine beyond the designed redline, though. The forces generated on reciprocating parts can reach a destructive level, and chances are you are going outside the peak HP curve anyways unless you are upgrading the cam, etc. more RPM doesn’t always equal more HP. __________________ 2021 Lifan Xpect EFI 2012 DF250rtc 1982 Yamaha Virago XV750 1982 Honda Twinstar CM200
	1

10-08-2021, 10:31 AM	#2
braindead0 Join Date: Jun 2007 Location: Reno, NV Posts: 89	The 1vdc reading on the spark coil is likely incorrect, the voltage is cycling at a high rate of speed so you're meter will not get a steady reading. If you're seeing 80VDC your regulator is shot.. I'm surprised those voltages didn't fry the CDI... You might want to verify your meter is in proper working condition.
	0

10-08-2021, 02:25 PM	#3
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	This might have an AC CDI, in which case you're measuring the wrong thing anyway.
	1

11-15-2021, 07:58 PM	#10
Newt232 Join Date: Oct 2018 Posts: 25	So I looked under the seat and of the four wires coming off the stator, one had broken about an inch from where it plugs into the regulator. I left the harness on the bike, and just resoldered the thing together where it was at. Voila! 13.something at the battery terminals! I may be selling this one now, I've got a lot on my plate and probably shouldn't be on anything with two wheels, but I'll miss this little guy a lot, that's for sure.
	1