The BMW GS boxer twin thread

**Phreaky Phil** · 7th November 2011, 20:22

Ive got a 19 AH battery in mine. I put it in as the plastic on the old battery was getting cracks in it. It was 14 years old an still going strong !! The 19 AH one is about 2/3 the size of the original and the rubber straps work using the slots in the bottom of the battery box. Made me wonder if some models used a smaller battery.
I think those really small batteries are Shorai Batteries. Dont think they've been out long enough to have a long term test, but they seem to work ok.

**Padmei** · 8th November 2011, 06:28

I'm going to borrow a DC ammeter & actually find out what my bike draws on startup. From there I can make some more informed choices.

**Crisis management** · 8th November 2011, 11:45

Bit of info for you Padders...

Pre 81 starters are rated at 270 Amp max draw, post 81, 320 Amp max (info from a manual), asuming you have a 10 amp hour battery, IE: will provide 10 amps for one hour at 12volts, it will provide 600 Amps for one minute or about 2 minutes of starter at max draw.
I'm looking at 20 amp hours batteries as that gives me about 4 minutes of starting at max draw.

**Eddieb** · 13th November 2011, 20:54

Airhead driveshaft rebuild kits in Aussie

http://www.advrider.com/forums/showp...&postcount=228

**Padmei** · 14th November 2011, 07:01

Thanks Eddie good spotting. May be cheaper from States tho now?
I got one universal replaced for $350 locally. Had I known there wouldn't be much difference in price i wouod have bought one of these.

**RAJAH1** · 14th November 2011, 13:08

Originally Posted by Padmei

I'm gonna research this a bit.

My bike starts pretty easily & isn't used as a commuter - only a Sunday avo bike so i don't need a lot of stop starting storage. I may even try my new MX type battery & see how that goes. A source has replied to me that motobatts can be installed on their side due to their unique manufacturing design which is interesting however I will double check on that. AGM or fibreglass mat batteries seem to be the way of the future.
I'm not worried about the length of leads as I will prob make some others up to suit.

I have had a look around & Antons site seems to provide the most specific advice. If you look right down the bottom he has some good calcs.
He seems to think 1amp/hr is all that is required for starting thereby once the alternator is up & running, charging the sytem you'll all good unless the draw from many appliances is greater than the output from the alternator. A 12A/H one is what he uses on his K75. Interesting.

http://www.largiader.com/articles/battery.html

They can be installed lying on their side have one in a bike at present and Mottobat have a battery that suits the monolever R80G/S. I will be needing one soon as mine needs the charger too often when not used for a week or so.

**Padmei** · 14th November 2011, 13:43

Cheers Rajah 1. I got an email from the importes saying they're ok to lay flat & no warantee/ performance issues. I just have to make upan appropriate holder.
I have noticed you selling a few bits & pieces on trademe so you must have an Alladins cave of goodies for airheads.

**RAJAH1** · 14th November 2011, 14:35

Originally Posted by Padmei

Cheers Rajah 1. I got an email from the importes saying they're ok to lay flat & no warantee/ performance issues. I just have to make upan appropriate holder.
I have noticed you selling a few bits & pieces on trademe so you must have an Alladins cave of goodies for airheads.

Have kept a few 'spares' in case of unfortunate incidents or failures. Sort of seems likely will always have a G/S ( managed to have one or two in my ownership fairly constantly since 1990 ) Not too much in the way of surplus to requirement bits now. I dismantled very doggy GS to get its frame and forks a few years ago to fix a written off low km bike. I'd also built up a stock of bits I decided were never really going to be needed. Still find the odd bit now and then that I get rid of though. You have a G/S Basic with a non standard headlight I have seen in Atawhai area?

**NordieBoy** · 14th November 2011, 18:32

Originally Posted by RAJAH1

You have a G/S Basic with a non standard headlight I have seen in Atawhai area?

More a Basic G/S...

**Padmei** · 14th November 2011, 18:55

Originally Posted by RAJAH1

Have kept a few 'spares' in case of unfortunate incidents or failures. Sort of seems likely will always have a G/S ( managed to have one or two in my ownership fairly constantly since 1990 ) Not too much in the way of surplus to requirement bits now. I dismantled very doggy GS to get its frame and forks a few years ago to fix a written off low km bike. I'd also built up a stock of bits I decided were never really going to be needed. Still find the odd bit now and then that I get rid of though. You have a G/S Basic with a non standard headlight I have seen in Atawhai area?

That my friend is the nicest compliment anyone has ever given me about my bike

Actually it's a R80GS that I say I'm modyfying- others would say I'm hacking up - It's all about perspective

I live on the Crescent there in Atawhai. I know your garage door too but just can't place it.