cb400 problem

Richard tea

Just want to make sure im good to go tomorrow with the install. The 3 yellow wires go to the RR. I have a black & red wire going from the RR to the Pos & Neg terminals on the battery. Ok so far so good. Im left with a red/white wire, a green wire & a green earth wire fom the stock RR connection. Do I just tape these up as they are not needed anymore?

Hotblack Desiato

Most bikes these days use permanent magnet alternators, the alternator output increases with revs, and the R/R just dumps the excess power as the revs increase. Older ones used electromagnets in the rotor a.k.a. 'field windings' and the R/R could vary the current in the field windings to control the alternator output.

IF your bike has field windings and this R/R isn't designed to cater for them, you're screwed I'm afraid

Are you absolutely sure this R/R is suitable for the model and year (and sometimes changes are made during a model year so you'd need to check the VIN as well.)

A bike with permanent magnet alternator and no field windings will just have 3 yellow wires from the alternator. If it has field windings then it'll have a couple of additional wires. Where do the extra wires go?

Richard tea

ninja900 wrote: »

Most bikes these days use permanent magnet alternators, the alternator output increases with revs, and the R/R just dumps the excess power as the revs increase. Older ones used electromagnets in the rotor a.k.a. 'field windings' and the R/R could vary the current in the field windings to control the alternator output.

IF your bike has field windings and this R/R isn't designed to cater for them, you're screwed I'm afraid

Are you absolutely sure this R/R is suitable for the model and year (and sometimes changes are made during a model year so you'd need to check the VIN as well.)

A bike with permanent magnet alternator and no field windings will just have 3 yellow wires from the alternator. If it has field windings then it'll have a couple of additional wires. Where do the extra wires go?

Ah bollox **** tits arse. Im not home till tomorrow so ill double check then. Thanks ninja
All the wires went into the stock rr. 3 yellow. 1 red & 1 green

CJhaughey

Out of the new R/R are two plugs, 1 with 3 yellow wires and 1 Black with 1 red and 1 black wire The 3 yellow wires connect to the alternator.
The black and red out of the other plug go to the Battery, there should be a fuse in between the red and the + terminal.
The lead with the double greens and a ring terminal goes to earth.
Your old connector is redundant now.

Richard tea

CJhaughey wrote: »

Out of the new R/R are two plugs, 1 with 3 yellow wires and 1 Black with 1 red and 1 black wire The 3 yellow wires connect to the alternator.
The black and red out of the other plug go to the Battery, there should be a fuse in between the red and the + terminal.
The lead with the double greens and a ring terminal goes to earth.
Your old connector is redundant now.

Ok ill fit the double green wire with ring terminal back to its normal position and tape off the other 2 wires.

Richard tea

Just connected up the mosfet RR. Readings are looking good ( I think ).

Idle im getting 13.5v

2000rpm =14.6v
3000= 14.16v
4000= 14.18v
5000&6000rpm = 14.20v

It didnt go over 14.20v at all no matter what the rpm.

The main thing is its charging at 6000rpm which the old rr didnt.
After 10 mins of reving the bike the new mosfet rr was still cold to touch. The old one would have been fairly hot.
Ill get to the job of fitting the new rr tomorrow

So those reading look good to you lads?

Hotblack Desiato

Those readings look very good, the voltage is going up to the required level at a nice low rpm (important for town riding) and isn't going above that when revved higher.

If you had an older type alternator with field windings, and there was no current going through them, then you'd get little or nothing out of the alternator.

I dunno if this bike has permanent lights on. If not, did you see a difference in voltage between lights on and lights off? You might get a bit less voltage with the lights on but it shouldn't really drop below 14V

Still though, it would be interesting to know where the 'mystery' wires went - I know they went to the old R/R at one end I meant where do the other ends go! It looks like you're in the clear, but it'd be interesting to know.

Richard tea

ninja900 wrote: »

Those readings look very good, the voltage is going up to the required level at a nice low rpm (important for town riding) and isn't going above that when revved higher.

If you had an older type alternator with field windings, and there was no current going through them, then you'd get little or nothing out of the alternator.

I dunno if this bike has permanent lights on. If not, did you see a difference in voltage between lights on and lights off? You might get a bit less voltage with the lights on but it shouldn't really drop below 14V

Still though, it would be interesting to know where the 'mystery' wires went - I know they went to the old R/R at one end I meant where do the other ends go! It looks like you're in the clear, but it'd be interesting to know.

The lights are always on. I forgot to mention that the headlight doesnt flicker or brighten when I rev now with the new rr:)
Yeah the problem was the old rr was working up to say 5500 rpm but over that it didnt charge the bat. So when I arrived into work after doing mostly 6000 rpm that bat was dying.

LOL:pac: The ''mystery wires'' I havent a clue. one is red/white & the other is green. At this stage if the bike is working and I can start using it again the wires can be going to another dimension for all I care:)

P.s, Im 99% sure someone is going to tell me that the ''mystery wires'' are highly important and my bike is at risk of blowing up if not reconnected:p

CJhaughey

ninja900 wrote: »

Still though, it would be interesting to know where the 'mystery' wires went - I know they went to the old R/R at one end I meant where do the other ends go! It looks like you're in the clear, but it'd be interesting to know.

They aren't mystery wires, the Red/Wh and Green in the bottom of the stock plug are the outputs to Battery from the old Alternator, via the Fuse/starter relay
Yellow in to the Reg/Rec and Red/Green out.

By fitting new wiring you will also avoid a problem with older electrics which is high resistance in the connections.
Modern plugs are much better sealed and resistant to water ingress.
Plus the new Mosfet Reg/recs are much better then the SH type.