nc24 rectifier replaced twice needed help!

[butterfly]

Hi,
My 1987 nc24 is having problems. I replaced the first rectifier because it was burnt out, it burnt the wires that are in the yellow plug & melted the plug a bit 2. I found this by it wasn't charging. I brought another unit in from the u.k as i live in nz. The second unit has lasted about a month now its not charging either. The engine note is different from when the first unit was on' to the second unit. Any help please before i have to buy another unit.

Cheers Mark

[bikemonkey]

You need to check your alternator output, and the current state of your battery too.

Wouldn't hurt to check all the charging system wiring either

http://www.400greybike.com/docs.htm <charging system check guide, same stuff for the NC24 I think.

[butterfly]

I checked the charging side after putting on the second unit by meter & it smend alright but it maybe faulty?

[bikemonkey]

What checks did you do on the alternator itself?

[speedy231278]

The correct output coming from the regulator isn't a complete guarantee that something isn't amiss elsewhere that could cause the charging circuit to fail. If all the components (ie battery, alternator and reg/rec unit) check out OK in themselves, there could be an issue with the wiring. It's certainly very prone to causing issues with the NC30 and 35.

[butterfly]

I have just checked the volt over the battery, i have just read the doucment highlighted above i will check this out tomorrow. What is also happing is the motor dies when you cum down to an idle, is this part of this problem as well. Could the icu be a problem as well.
cheers for any help

[bikemonkey]

What voltage did you get across the battery?

We'll need voltage whilst bike off and whilst running at idle and 5k rpm.

Plus the other figures from the checks in that guide.

The stalling at idle could be a number of things, could be your battery isn't getting enough juice/doesn't have enough just to hold idle, could be your carbs pilot circuit, could also be the ICU as you say.
One problem at a time, get those checks done first

[butterfly]

I will check 2morrow, THanks for the help so far.

[Neosophist]

Melted plug doesnt always mean the regultor rectifier unit is dead.

That plus connects the generator to the reg/rec unit. Overtime it gets shitted up due to the weather and what not, unless its cleaned somewhat regularly and some contact spray etc put on to coat it it will oxidise up.

This connection carries a lot of power so if the connection of the plug becomes weaker due to oxidising and general shit in the plug heat soon builds up and melts the plug.

Restoring that connection will often fix a reg/rec. You MUST solder new conections on if you replace them, crimping alone isnt enough.

A full electric test won't take long, maybe half an hour.

Check the output from the generator and the resistance, if it passes check your battery charge level.

Next check the output from the generator at idle and 5000rpm with lights on and off.

If you have any problems replace and fix.

Your other issues could be related but without seeing the bike its hard to tell, so I suggest fixing the electrical system first, it is the most straightforward and easisest thing to sort on the bike.

Once that is all upto scratch see if your other issues go, if not then report them up and we will figure them out.

[butterfly]

Hi, we have done the tests and these are the results
-battery bike not running = 11.97v ( note: bike was ridden the day before the tests)
-bike running, @ 5k - 13.33v
-bike running, lights on @ 5k = 12.6v

completed ohms tests on the plug wiring, all results were 0.4ohms
completed resistance tests on all pins in the plug wiring, all results were 0.4ohms as well

Thanks for all your help