Nc30 Charging problem

[dave_c24]

Hi guys,

firstly Happy new Year. ive got a bit of a problem with the NC30. just before christmas the bike start showoing signs of battery problems. on inspection the battery did look very old so i replaced it thinking the cold had taken its toll. as i had the back off i tested the rectifier as in the haynes and also checked the charging system was putting the right voltage in. i was getting 13.5v at 5000rpm with lights off and only 12.2 with lights on? i dont think this is right but it seemed fine so i started using it again. i must add that i did the healight mod to change to 60w bulbs around 4months ago without any probs until now. within a day or so the lights began to get dimmer and dimmer whilst riding but if swithced to sidelights the biek would charge again.

when i reached work i then checked battery voltage and it had got down to 11.8v with the bike off and will only get to 13.2v when the bike is running 11.9v when the lights are on at 5000rpm. i decided then to test the alternator as in the hanyes and all is fine. i got 0.4 ohms on each wire and also none of the earthed out. i then decided it must be the rectifier so did the conversion the the R6 one as i thought brighter bulbs may need a bigger rectifer. but the bike is still the same?

i have recharged the battery off the bike and on Friday straight off charge it read 13.5v without being hooked up to anything. i then checked it saturday still not connected and iot had droped to 12.8 it is now tuesday and it is on 12.7v is this normal for a new battery to lose charge like this or could this be the problem?

any help would be greatly appreciated

[CMSMJ1]

Sounds like the generator is goosed. Have you checked thr output of it in AC? Should be more than 50 IIRC

[dave_c24]

Sounds like the generator is goosed. Have you checked thr output of it in AC? Should be more than 50 IIRC

thanks for the reply, could you tell me the correct method for checking the output and also confirm what iirc stands for? i will test it straight away

cheers dave

[CMSMJ1]

Howdo - The test is in the Haynes manual.

it is for the AC output through each of the 3 phases of the generator.

IIRC = If I recall correctly....sorry..been a geek too long

You need to unplug the large white connector block by your right knee - it has 3 yellow wires into it (and may be charred or melted)

You need a multimeter set to AC volts (200 range)

Use the probes on each of the wires in turn - call them A B C - connect A+B then B+C and A+C in turn withthe probes when the engine is at 5k revs. You should see at least 50V though each phase. The voltage should rise and fall as the revs do. If you don't get the full beans on one of the measurements then the generator is likely on the way out and not charging the battery.

I had the exact same issues as you describe - running OK with no lights but with lights on I would end up out of power.



This is why...

[dave_c24]

Howdo - The test is in the Haynes manual.

it is for the AC output through each of the 3 phases of the generator.

IIRC = If I recall correctly....sorry..been a geek too long

You need to unplug the large white connector block by your right knee - it has 3 yellow wires into it (and may be charred or melted)

You need a multimeter set to AC volts (200 range)

Use the probes on each of the wires in turn - call them A B C - connect A+B then B+C and A+C in turn withthe probes when the engine is at 5k revs. You should see at least 50V though each phase. The voltage should rise and fall as the revs do. If you don't get the full beans on one of the measurements then the generator is likely on the way out and not charging the battery.

I had the exact same issues as you describe - running OK with no lights but with lights on I would end up out of power.



This is why...

right ive jus tested the generator and i got 40v,40v and 42v at 5000rpm if reved harder the voltage goes higher 58v

the pic definately shows the cause of yours lol. how sure are you of the output voltage at 5000rpm?
cheers dave

[dave_c24]

dont suppose the NC24 had the same Generator in it, jus so hapens that i have a complete NC24 engine in the shed that i know is good?

[hardnutdvd]

there is an excellent link in one of the post in this section that gives you a complete step by step guide to testing...
do a search on alternator or rectifier. there will be the link in more than one of the posts.

I was told by a member on here you should be looking at 45-50volts at 5k rpm on each wire.

[DoktorMandrake]

Honda AFAIK don't give a specific output figure for their alternators on any of their bikes but 50v at 5k I would think was reasonable to expect from a 400. If you're running the bike with the alternator unplugged it's important to unplug the alternator before starting the bike and make sure the bike is switched off before reconnecting it.

You can also check ya alternator by setting your multimeter to continuity/bleep tester and putting one probe on each of the phase outputs in turn and earthing the other probe. This is a fairly good way of checking if your alternator is shorting to earth (a good sign it's knackered as it should be insulated which obv if it's cooked like CMSMJ1 there's a good chance it won't be) and you can test the internal resistance of the windings by testing each of the phase outputs against one another. Ideally you want as low as poss without open circuit but no more than 0.8 ohms.

Then you can test the reg/rect - set it to ohms again and check each of the three points where the alternator connects against each other. Should be higher resistance one way than the other. If you get low resistance both ways or high resistance both ways then it's fucked. Think that's how you do it anyways. Been a while since I checked a reg/rect but it's a simple test and it usually detailed in most Haynes. You make a table and check each of the points against each other.

[dave_c24]

cheers for the replys guys, i get 40v ac from each of the generator wires and 0.4ohms on the alternator windings and no earthing out on any of them. rectifier is good as has been replaced battery is new. think im going to take the generator out to see if its in any way like CMSMJ1 old one. other than that i dont know what to do.

would a NC24 generator fit the NC30?

[CMSMJ1]

Not sure if the 24 would fit or not - one of the guys who know that will be aloing..I am sure!!

I do have a spare set of windings if you need them - I run a modified gsxr genny in mine so my 30 one is spare...and it is not the toasted one..lol