Regulator/Rectifier

[David]

No I haven't sorted this yet.
I have ordered a strap wrench, so once this arrives I will hopefully get the Flywheel off and be able to see the Stator.
I came across a post where someone had used one of these to provide the hold required whilst removing the 14mm nut.

I did think it must be the reg/rect as I was getting same ac voltage across all 3 phases
but
I measured the resistance again between all 3 yellow wires from the Stator and although it said 0.5 Ohms,
after a couple of seconds this dropped to 0.2 Ohms.
This happened between them all
I believe they should read 0.5 Ohms - 2 Ohms, so they are to low

I will replace the stator first as the Reg/Rec and battery were renewed not that long ago
Will keep you posted

Cheers

[Neosophist]

The resistance sounds fine to me.

It should read 0.1 - 1.0 ohms.

However, if you set your multimeter to ohms and touch the two leads together, see what value you get, a lot of meters will give you a value like 0.4 etc, which must be subtracted from the value you are given on the meter as this is the meters internal reistance.

Check the restistance between each yellow wire and earth (frame) it should not read anything. If it does its indivative of a short to earth.

None of these tests are under load and the insualation could be breaking down when a load is placed on the genny. There are load tests you can do but it sounds ok at the moment.

I've had gennys that tested ok but were breaking down under high load.

[David]

I managed to get the Flywheel off using the Strap Wrench as a holder - £7 from ebay, very handy tool and an M20 bolt to pop it off

This is what it looks like front and back.
Do you think it looks like it needs renewing?

[Neosophist]

That looks fine, one of the phases has gotten a little hot by the darkening of the insulation but you CANNOT tell by looking at it.

Unless of course it looks like the one Mark posts all the while (it had basically set on fire!)

I've seen black ones that work fine, they'd just got hot.

Your resistance sounded normal to me.

Lets start from the beginning as it'll save you time / effort / money.

You batterys going dead yep?

This is usually bad reg-rec / duff battery (quite often both)

What happens is the standard reg/recs can't dissipate a lot of heat... older / neglected batteries (i.e. short journeys with lights on, not kept charged) start to break down and can't take a higher charge rate anymore.. the reg-rec has to burn off the excess power as heat.. since there dinky reg/recs they overheat and die.

If left un-checked this will often melt the genny as well.

So...

1. How old is the battery?
You can get a new Varta one for 19.00 (always recommend a new battery)

2. Is there any resitsance between the yellow wires and earth (frame) when the genny is bolted in.

3. What voltage were you getting between the yellow wires at 5000rpm (yellow wires unplugged from Reg/Rec) you need to measure them in AC volts.

It sounds like you just need a new reg-rec (get an R6 one) and replace the battery. Should cost you about 45 quid for both.

[David]

Battery is about 18 Months old, but I've hardly used the Bike. I've been charging with trickle charger keep it charged up. It's a Rob Hunter model.

The genny is giving me 20VAC at idle and 75vAC at 5000rpm
Checked between each yellow wire and frame - no shorts
When I rev the bike the DC volts across the battery goes down below charging voltage

Th Reg Rec is a newer one they replaced at the garage about 7/8 months ago - has large Heat Sink surrounding it.

BUT

I think I'll get an R6 one and probably get a new battery as you've recomended as it might be faulty now with all the charging problems

What Varta battery is ok for the NC24?

Cheers

[Neosophist]

That souds like your reg/rec is dead.

I wouldn't keep the trickle charger attached all the while, only once a week until its charged.

But... 75v @ 5000rpm is high for the generator. It should be 50v.

I'm a bit concerned that this voltage might over-load the reg/rec.

http://www.tayna.co.uk/YB9L-B-12N9-3B-P790.html

that battery

[Morespeedvicar]

Hi,
just wondering if your multimeter is over reading. if it was me I'd just try another reg/rec on it and see wat happens. i would of thought the output voltage would get lower if it was bunring out.
Do you have another multimeter to try it with?
Cheers
Ian

[cbr400rrn]

I have a spare R6 rectifier that i once bought and put it away in a safe place then couldnt find it when i wanted it, so purchased another and lo and behold it turned up in the end. if you want it give me a P.M

[Neosophist]

Hi,
just wondering if your multimeter is over reading. if it was me I'd just try another reg/rec on it and see wat happens. i would of thought the output voltage would get lower if it was bunring out.
Do you have another multimeter to try it with?
Cheers
Ian

Well if the Reg/Rec is putting out 75v at 5000rpm (which seems too much to me) the r/r could be breaking down under load and failing to supply voltage...

I had an electrex world reg/rec that died like this.

+1 on try another multimeter though, just to see.

[thunderace]

But... 75v @ 5000rpm is high for the generator. It should be 50v.

I wouldn't worry about that if he's using a Yamaha reg/rec. All Yamaha 4 strokes kick out around 75Vac at 5k rpm and the reg/recs are designed for it.

Mine kicks out the near the same on each phase. Do you think it's possible that the spec was changed when the later genny was fitted in the factory? ie; the earlier one kicked out 50V and the later 75V to bring it in line with everyone else?