Replacement Alternator 09 GSA

Hi Pale Rider,
My alternator has hung on and not yet failed so I have not yet replaced it. From what I have seen the easiest way to go is a Bosch alternator part number 0124120007 from an 05 - 07 RT. Try to get one with the pulley attached. You will then need a harness adapter to convert from the Denso plug to the Bosch plug, I am still looking for this as part number 7691724 appears to go the wrong way looking at the harness adapter and pictures of the plug on the Denso alternator, if that is the case then the Bosch plug will have to be purchased and the Denso plug replaced. Any inmate did this with a BMW repair plug. Ian J Hartley posted a great list of which alternators, pulleys and belts worked together on another post which was very helpful in working out which alternator to keep an eye out for. Although the casing on mine was split the pulley rotated fine and the battery still gets a charge, so I thought I would leave it till it did fail. Has yours failed?
Waggy
 
I’ve posted these pictures a few times previously as I’ve replaced many a seized 1200 alternator and also posted pictures of the grisly remnants of scrap that’s left afterwards 😄
 

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Hi Steptoe, I have looked at that adapter and I do bow to your greater knowledge but I am not sure that the white end will plug into the plug that is on my 2005 GS that has the Denso alternator on it. I mentioned that in my post but the plug in the adapter is female with the alternator being male. This means that I will need to chop the Denso plug off and use a repair plug so that I can fit the Bosch in. But as I said I might be missing something or miss understood where the adapter is used
Waggy
 
Hi Steptoe, I have looked at that adapter and I do bow to your greater knowledge but I am not sure that the white end will plug into the plug that is on my 2005 GS that has the Denso alternator on it. I mentioned that in my post but the plug in the adapter is female with the alternator being male. This means that I will need to chop the Denso plug off and use a repair plug so that I can fit the Bosch in. But as I said I might be missing something or miss understood where the adapter is used
Waggy

Use a Bosch adapter.
 
Looking at Ian’s list with a 2004 would it possible to use a Bosch from RT (10) and swap the crankshaft pulley over, as I was looking at the Bosch (007) but needs a Free Wheel unless that is already attached to the alternator? But with the one from an RT (10) being newer it would make more sense to fit that.
 
Hi Pale Rider,
My alternator has hung on and not yet failed so I have not yet replaced it. From what I have seen the easiest way to go is a Bosch alternator part number 0124120007 from an 05 - 07 RT. Try to get one with the pulley attached. You will then need a harness adapter to convert from the Denso plug to the Bosch plug, I am still looking for this as part number 7691724 appears to go the wrong way looking at the harness adapter and pictures of the plug on the Denso alternator, if that is the case then the Bosch plug will have to be purchased and the Denso plug replaced. Any inmate did this with a BMW repair plug. Ian J Hartley posted a great list of which alternators, pulleys and belts worked together on another post which was very helpful in working out which alternator to keep an eye out for. Although the casing on mine was split the pulley rotated fine and the battery still gets a charge, so I thought I would leave it till it did fail. Has yours failed?
Waggy
Hi and thanks for your reply. No mine hasn’t failed as of yet but after reading the many posts on the ones that have I really want to get it changed over asap, I’m doing a European trip this summer and don’t want the worry.

One thing that slightly concerned me was the Denso one being 60 amps and 13.8 volt output but the Bosch one pushing out 55 amps but 14.4 or 14.8 volts, does this mean I will have to change other stuff like maybe a voltage regulator etc?
 
Ok so im getting a 0124120015 alternator and am still puzzled as to how to wire it up, the plug in Steptoes post above looks like the standard plug connector for the Denso alternator that I already have, so if i get the £30 plug from Motorworks with the two wires on the other end do I need another plug to solder on here?? Or do i solder to some exiting wires? Also on both the Bosch and the Denso there is a hefty bolt down terminal on top of the alternator so I’m guessing this just swapps over ? Will I also need a different voltage regulator or is that part of the alternator and lastly what’s a zennor diode and is it necessary to remove it from the Bosch. All very confusing as wiring just isn’t my thing
 
Ok so im getting a 0124120015 alternator and am still puzzled as to how to wire it up, the plug in Steptoes post above looks like the standard plug connector for the Denso alternator that I already have,

I believe that some of the bike wiring harnesses originally came with the connector to fit Bosch alternators, but somewhere along the manufacturing process, they decided to fit Denso alternators instead, hence the need for the adaptor cable.

so if i get the £30 plug from Motorworks with the two wires on the other end do I need another plug to solder on here??

No. The plug from Motorworks is a repair plug. It is designed so that you cut off your existing Denso plug and then solder on the repair plug leads to the wires on your bike where the Denso connector was.



Also on both the Bosch and the Denso there is a hefty bolt down terminal on top of the alternator so I’m guessing this just swapps over ?

Correct.


Will I also need a different voltage regulator or is that part of the alternator.

No the voltage regulator is built into the alternators



and lastly what’s a zennor diode and is it necessary to remove it from the Bosch. All very confusing as wiring just isn’t my thing ��

The Zennor diode is the overvoltage protection Diode which is fitted externally on the Denso alternator. The Bosch alternator has it’s own built in overvoltage protection, so there is no need to transfer the diode from the Denso to the Bosch, but if you do, it will probably do no harm.
 
I believe that some of the bike wiring harnesses originally came with the connector to fit Bosch alternators, but somewhere along the manufacturing process, they decided to fit Denso alternators instead, hence the need for the adaptor cable.



No. The plug from Motorworks is a repair plug. It is designed so that you cut off your existing Denso plug and then solder on the repair plug leads to the wires on your bike where the Denso connector was.





Correct.




No the voltage regulator is built into the alternators





The Zennor diode is the overvoltage protection Diode which is fitted externally on the Denso alternator. The Bosch alternator has it’s own built in overvoltage protection, so there is no need to transfer the diode from the Denso to the Bosch, but if you do, it will probably do no harm.

Fantastic reply, I really appreciate it I’ll let you know how I get on ��
 
Ok just done the Bosch alternator conversion on my 2012 gsa. First thing the wiring is different in that it has the Denso plug directly joined to the wiring loom, no short double ended plug as in Steptoes post above. I ordered the £31 conversion lead from Motorworks but noticed they had only charged me a fiver for it so I thought I’d wait and see what they had sent me, turned out they had snipped a Bosch plug off of an RT loom, even better!! After some initial confusion regarding which wires go were i snipped the Denso plug from my loom and soldered the white wire from the RT plug to the blue wire on my loom, as the Bosch alternator only has one terminal I tapped up my green loom wire and the blue and white wire on the new plug, fired it up and runs perfectly.
 
Evening all, took my 2012 GSA out last Friday to go away for the weekend and noticed it wasn’t charging in the first hundred yards. We checked it out and there was no power. It’s done 75000 miles and I’ve ridden it for 7 winters and was expecting the split Alternator casing but it was quite clean with no damage. Anyway, I took the end cover off and the brushes and the armature were fine so I got our local auto electric firm to have a look. He couldn’t fit it in his test bed but did say there is a short inside when he connected to the electrical socket.
So the burning question is does anyone have a regulator/rectifier from a split working alternator that I could beg or buy?

Thanks.
 


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