Hey guys, I'm having a really puzzling problem with my NC30. The bike just won't seem to hold a charge. I rode it back through town from my friend's house and unless I kept it at about 4k RPM at traffic lights, it would conk out. We managed to bump start it once, but the second time it died it was having none of it. We had to drive back, grabbed jump leads and limped home. I spent today with the Honda manual running through various troubleshooting exercises with a multimeter, but the reg/rec, alternator and battery all seem to check out OK. It seems to run fine and start on the button without lights, but has real problems with the lights on. Any ideas?

hello-

sounds to me like you have a gubbed alternator,it may be putting out a charge but not enough to charge the battery when you are using lights etc.

what to do is disconnect the block connector by your right knee that has three yellow wires,what you want to do is test the side that comes from the alternator and set the multimeter to ac volts.....if it has a range on this setting then it has to be a minimum of 50.

with the bike idling @5000rpm take three seperate readings and they should all be 50volts or above and all the same,if any are below 50v or different then your alternator is suspect.

i reckon what's happening with your bike is the battery is getting a slight charge but when you use your lights it is draining faster than it is getting charged.

another test to do which could implicate this is a simple charge rate test at the battery.set the multimeter to dc volts and check how much charge the battery is getting @5000rpm.....it should be between 13.5-15volts,i believe your's will show less than 13 volts @5000rpm


william

do a search. I started a thread called 'help,do i need a new reg rectifier'.There was loads of great help. I changed my battery, rectifier and alternator in the end.

Have a search!!!
AL

Cheers guys. I had done a search previously and read your comment about the alternator test at 5000 rpm. I've yet to do this one, but I have already tested my battery in the manner described and was reading around 13.4V. I'll try the alternator test tonight, cheers guys.

13.4volts is below the minimum

when i had this problem earlier on in the year my charge rate was roughly 13volts but as the week progressed it was getting worse and worse....

my alternator was putiing out 3 seperate readings of around 30 volts,yours may be slighly higher as the charge rate is half a volt higher than what mine was.......


william

My Dad spoke to a guy at Woodford Motorcycles about this when he went to grab a new battery for me (I was at work), and he seemed to think that the alternator should be putting out at least 70V@5000rpm. Well, I think it needs to wait for a day when I'm not back late from work and the neighbours aren't all tucked up in bed before I start testing the alternator. I'll let you know how it works out, though. Thanks again, guys.

it's definately 50volts,it is a three phase alternator so you take three seperate readings(3 pins)

all should be a minimum of 50 volts or above and if any are below or different from the rest then it is gubbed.

last thing you want to do is piss the neighbours off with your bike revving its tits off


william

Hiya,
make sure all the eatrh connections are good and clean as well.
Cheers
Ian

Well since replacing the battery everything seems to be tickedy-boo. It starts on the button and, once up to temperature, appears to run fine. Think I'll still look into the alternator just to be on the safe side. Thanks for your help, gents.

My first idea is fooked battery.

Second idea is bad earth(s).

Charge voltage is a little low but could be the battery. See how the new one goes.