NC30 charging probs

[MadDogRoger]

Hi all,

I have this electrical problem with my NC30 that has been dragging on for a year now. I've tried all sorts of things but haven't solved it yet.
Here's the story.

About a year ago I start getting problems with my indicators not working. Having had that problem before and solved it by cleaning out the switch gear, I tried that again. No result.
Completely dismantling the switch gear again, to as far as you can possibly get it, clean everything, bend everything in place etc. It's better but not perfect.
It would mostly work fine at medium revs (4-6000), but when halted at traffic lights, on idle: sometimes it wouldn't work.

Then one sunny afternoon, while driving home from work, she cuts out on me while waiting for a traffic light. Completely dead battery. Starter motor is unable to start the bike. Have to phone the wife to come with jumper cables and screwdrivers. Wait for an hour. Jump start the bike and it immediately runs, drive home OK (25km) and hook it up to the charger.

Couple of weeks later same thing, at a different traffic light. Starting to get annoyed here and decide not to call the wife, push start the bike, it starts and I make it home. That was the last ride before winter.

Then after winter, first ride to work is OK. Second ride, indicator probs pop up again. Third ride: the bike cuts out on me on the way home 4 times.
Manage to get it push started every time but

What I have done so far after that:
- measured battery tension: 11.8V, so dead battery. But it's not an old one (one year), so charged it and 13.6V
- checked the ground from the battery (on the frame): absolutely spotless, so that's not it.
- measured tension on battery while engine is running: approx 12.5V, way too low. So figured bad rectifier/regulator. Honda ones are not good and expensive. After market will set you back a fair amount also, so figured I'd give the Aliexpress a go at 8€. Got it within 2 weeks. Needed only minor filing to fit to the bike. After placing, tension on the battery was up to 13.5V. Not the 14.5V I'd hoped for but better than the 12.5V I had. So happy faces.
- cue a couple of trips to work. Problems with indicator lights pop up again. Then one morning I'm only 10km from home when the bike cuts out again. Decide to double back home, after push starting, and take the car. It's not going to make the 40km trip to and from.
- Today I measured the generator. I got 0.1 Ohm on all the coils. AC voltage was around 30V when at 2000 rpm and would steadily go up to 42V at 4100 rpm. So that all sounds pretty good. The connector between the coils and the wires to the regulator/rectifier seem pretty, how shall I put it, cooked
Not melted but a bit brownish.

I've done some searching on the web and read a story of a guy with the same problem and measurements. For him it turned out to be the generator, even if the voltages were OK???
Is it true that taking off the generator cover draines the engine oil? Is the generator running in oil??? That sounds really weird to be, even if it's just because of the resistance of the flywheel in the oil.

It could also be that the cheap Aliexpress rect/reg is faulty. I read somewhere that an R6 item can act as an replacement. Is that true? If yes, any specific model or all models?

Any thoughts are greatly appreciated to help tackle this problem.

Thanks in advance.
Cheers
Roger

[magg]

You do not specify the rpm or electrical load when you measured 13.5 volts at the battery.

[MadDogRoger]

The 13.5V was measured after start up, so still on choke. Rpm was approx. 2500. Even revving it up to 3500-4000 didn't change the voltage, it was stable. I'm not quite sure, but I think the lights were turned off at that moment.

[magg]

Do you normally run with headlights on? Have you checked the main fuse connections located in starter relay unit? Have you checked the wiring loom earth connection located just in front of the front ignition coil? You might consider directly linking the -ve output of the rect/reg to the -ve terminal of the battery.

[NGneer]

Firstly I (personally) would not trust the cheap and chearfull Chinese Reg/Rec. I suspect you have other issues with your charging System but even if you manage to fix them you could easily cook your whole charging System afterwards just because you saved a few quid on a cheap Reg/Rec. The R6 ones work if you can find one or you can get a robust replacement item from Graeme France or Rick Oliver.

I would be tempted to take the L/H cover and flywheel off and check the wires and Generator - I suspect they may be a bit cooked and subsequently breaking down when warm. Also check the plug that Comes from the Generator across to the RH side of the bike. I have had one of those cooked in the past (see pics below)




The charging System may be the Achilies heel of these bikes, but it is not overly complictaed (and I don't like electrical stuff). You seem to have checked most elements so for my 2p worth I would check the generator and its wiring/plugs next address as required then treat it to a proper Reg/Rec and a new battery. I know there are other guides out there but I have used this one for a few years now and it works for me, hope it helps (https://cdn.shopify.com/s/files/1/1091/ ... 9374954073)

[MadDogRoger]

Do you normally run with headlights on?
Yes, always high beam on. Get a lot of friendly blinks back from car drivers but hey at least they saw me

Have you checked the main fuse connections located in starter relay unit?
Yes, these are in perfect order. Also took out the main fuse to see if it made a change. No corrosion there.

Have you checked the wiring loom earth connection located just in front of the front ignition coil? You might consider directly linking the -ve output of the rect/reg to the -ve terminal of the battery.
Haven't checked the loom earth connection yet. Will certainly do so. I can also easily hook up the rect/reg directly to the battery to see if it makes a difference.
Thanks for the tip.

[MadDogRoger]

Firstly I (personally) would not trust the cheap and chearfull Chinese Reg/Rec. I suspect you have other issues with your charging System but even if you manage to fix them you could easily cook your whole charging System afterwards just because you saved a few quid on a cheap Reg/Rec. The R6 ones work if you can find one or you can get a robust replacement item from Graeme France or Rick Oliver.

I know it's a risk with the cheap Chinese part, but since I wasn't sure that the rect/reg was actually the problem, 8€ sounds a lot better than 150 pounds for testing. I also ordered (but haven't received yet) a digital voltmeter, that I intend to install to monitor the voltage while riding. See if it gradually drops (not charging) or if it's a short circuit of some sort that pops up


I would be tempted to take the L/H cover and flywheel off and check the wires and Generator - I suspect they may be a bit cooked and subsequently breaking down when warm. Also check the plug that Comes from the Generator across to the RH side of the bike. I have had one of those cooked in the past (see pics below)

Taking of the cover and flywheel is kind of my next step. Do I have to drain the engine oil for this??
The plug that comes from the generator looks better than in your picture. I'll try to post a pic tomorrow.


The charging System may be the Achilies heel of these bikes, but it is not overly complictaed (and I don't like electrical stuff). You seem to have checked most elements so for my 2p worth I would check the generator and its wiring/plugs next address as required then treat it to a proper Reg/Rec and a new battery. I know there are other guides out there but I have used this one for a few years now and it works for me, hope it helps (https://cdn.shopify.com/s/files/1/1091/ ... 9374954073)

Thanks for the link, it's helpful. I'm a mechanical guy myself and electrical is harder for me. Keep you guys updated on the progress.

[magg]

If the rect/reg has a metallic base, you should make sure the mounting plate on the chassis is flat and use thermal transfer compound between the rect/reg and the chassis mount plate, helps remove heat from the rect/reg.

[MadDogRoger]

If the rect/reg has a metallic base, you should make sure the mounting plate on the chassis is flat and use thermal transfer compound between the rect/reg and the chassis mount plate, helps remove heat from the rect/reg.

Yes you're absolutely right. That's why I took the file to the new RR. It was marginally bigger than the old one. And as you know the mounting surface on the VFR has reinforcement ribs, so the RR would not sit flat. Literally one minute of filing was enough to get it flat. I didn't us transfer compound since it wasn't used with the original but you're right that is even better.

[MadDogRoger]

Here are some pictures:








Not looking super but then the bike is 25 years old. By the looks of the contacts I don't think that's the problem. Nevertheless I cleaned them before fastening.