Alternator upgrade

Drew595

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Hi
This is my first post so sorry if it's in the wrong place.

I have a 55reg r1200gs (not an adventure) with a BIG split in the side of the alternator, BMW as you probably know want about £400 for a new one of these, so am looking at replacing it myself with a 2nd hand item.
I'm having trouble sourcing one with my part # 2306280 (40A) in this country, they all seem to be in the U.S. I have tried loads of breakers, motoworks, motobins & eBay.
I have found a few that say they are off 2011 adventures they physically look the same but I believe they are 50A

Anyway do any of you guys know if I can replace the 40A with a 50A without damaging my electrics?

Thank you in advance for any help

Andy

I have a had a good look through the forum and can't find an answer, sorry if it's duplicated.
 
This breaks my heart... I so wish I could provide a definitive answer, but I can't.

Thinking about it, there seems to be no real reason why the 50A alternator shouldn't just slot right in.
With the ability to generate greater current comes slightly more electromagnetic drag, but that shouldn't be a huge factor.

The $1 000 000 question is: will the ZFE-High throw it's toys out of the cot?
Going on a hunch, I'd say 'No'. On the other hand, if it does, it will immediately cut off the incoming current (and thereby 'isolate' the alternator from the rest of the electrical net).
If this happens, you'll know immediately: the master caution (yellow warning triangle on the display) will light up, and you'll get a charge rate warning.

Remember: all that extra 10 Amps is there for is to be able to power extra accessories, if and when needed. The extra current, in and of itself, will not cause mischief.
 
Och Aye - I just had a brain buzz.

Why not have a chat with a local light engineering works?
If they're any good at all, they will be able to fit the alternator casing back together, weld it back into a single piece, and weld on reinforcement plates so that it will never crack again.

G'wan... gitt a try! :bounce1
 
Drew595 said:
Hi
This is my first post so sorry if it's in the wrong place.

I have a 55reg r1200gs (not an adventure) with a BIG split in the side of the alternator, BMW as you probably know want about £400 for a new one of these, so am looking at replacing it myself with a 2nd hand item.
I'm having trouble sourcing one with my part # 2306280 (40A) in this country, they all seem to be in the U.S. I have tried loads of breakers, motoworks, motobins & eBay.
I have found a few that say they are off 2011 adventures they physically look the same but I believe they are 50A

Anyway do any of you guys know if I can replace the 40A with a 50A without damaging my electrics?

Thank you in advance for any help

Andy

I have a had a good look through the forum and can't find an answer, sorry if it's duplicated.
Click to expand...


assuming that the GSA also has a bigger battery then the only risk might be that the GSA has a thicker cable twixt alt and battery to carry the potential higher charge current, to be super safe it might be worth checking that the cables are the same size on both bikes but even if not unless you dangle loads of electrical trinkets on your bike I doubt it will ever need to charge high enough to trouble the cable that's there
 
Not sure about the 1200 but on the 1150 it was a straight swap from a denso 40a to a bosch 50a as long as you use the correct brackets. Battery and wiring all the same
 
Hi thanks for all the responses.

I've not come across this ZFE before it sounds expensive if I burn it out?
I like the idea of fixing the split but it looks like the grand canyon and pritty furred up.

Thanks for the link to the alt in lithuaina I think it's a 50A

Not sure about the pulleys I think the adventure has a free wheel unit but Im sure I've read they are interchangeable.

I'll check the gauge of Cable to the battery on my mates GSA,

Am I right that the 50A alt will only kick out more juice IF demanded but not continuously, but if it's on my GS that only demands 40A then that's all it will output?
 
I think it shoud be OK at 50 amps, providing the mechanics are the same or interchangeable.

Why not shove your mate's in an see what happens? If all is good, then you'll be able to source a 50 amp version quite quickly it seems. If it goes pop... Well, it wasn't going with the cracked one and you couldn't source one for under four hundred anyway.... Plus whatever else the 'pop' takes with it.

To answer your other question, most alternators do not kick out full power unless the real need for them to do so exists and then in quite short bursts. It's called the duty cycle or summat like that, I think. Most will just tick along well within their power rating, unless you start hanging all sorts of other gubbinry on.
 
I think bikes with ABS and heated grips fitted as standard had a 50W alt. If yours doesn't have ABS then that could be the reason. Was certainly the case with my old 1150 which had a 40W and no ABS. Should be near enough a straight swap though you may want the beefed up mountings. If still in doubt, ask Steptoe.
 
A Google search of the question turned up ths thread.... Though it reaches no conclusion....

http://www.advrider.com/forums/showthread.php?t=766990

Another thread on the same topic questioned whether the connectors were the same.

It's a safe bet that if you have any question, someone will have asked it before.... And maybe found an answer. This time around, Google really may be yir best friend. I suggest starting with: 50 amp alternator in 1200 gs and going on from there.
 
Good thinking about trial fitting the alternator out of my friend GSA but I can't see him going for it, tight so and so.

Had a look on motoworks, your right according to their listing the 40A is interchangeable with 60A from the 2008 onwards.
Before writing the original post I spoke to m.w about any alternatives and the chap didn't know, I'll ring them again in the morn. Cheers
 
Well just as it says on the moto works website the GSA 60A and the GS 40A are interchangable you just have to swap the pulleys over (not as easy as it sounds) you need to hold the shaft with a 10mm whilst getting a 22mm offset ring spanner on the lock nut but the shaft is very soft and the nut VERY tight.

Found a 60A on eBay for £120. I've done 100 miles so far since fitting with no problems.
Talked to the guys at moto works and they say the only reason the 55A isn't a straight swap for the 40 is that the loom connector is a different shape.
Worst part of the job - fitting a new aux belt.

Thanks for all the help guys.
 
maybe the 10mm nut is threadlocked. Try some heat from a small blow torch direct onto the nut. Ideally use a temperature marking crayon so it does not get above 150 degs C.

A hot air gun will do the same job if you can fit a small air nozzle. Otherwise it risks overheating the alternator case/frame.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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