Hi Guys 
I have an 1986 K100RS
Ive started my quest to get my bike back on the road 
been sitting for around 6 years 
Last time i had it going after replacing fuel pump & draining fuel & a few other bits was running but needs other works such as new rear brake cylinder 
are there some recommendations for secondhand spares ?
also need some help to remove OEM alarm after installing new battery the horn is constantly going off 
I take it the alarm is causing the problem 
Ive found some topics on the alarm & wondering if anyone has removed the alarm & what they did to remove & what wires had to be reconnected ?
many thanks for your help !

Welcome!  the master cylinder and fuel pump have reasonably priced replacements available.  For example, a usable rear master cylinder can be had for under $20 dollars and there are fuel pump kits that have the mount and the damper for under $100.  Members here have used them successfully on their bikes.

thomo wrote:Ive found some topics on the alarm & wondering if anyone has removed the alarm & what they did to remove & what wires had to be reconnected ?

Is the alarm like the one pictured and discussed in this thread?

More info on Gryph's suggestion. Master cylinder http://www.motobrick.com/index.php?topic=9364.msg128997#msg128997 and Fuel pump http://www.motobrick.com/index.php?topic=10054.msg86054#msg86054 Both the master cylinder and fuel pump still performing very satisfactorily.
Regards Martin.

Laitch wrote:

thomo wrote:Ive found some topics on the alarm & wondering if anyone has removed the alarm & what they did to remove & what wires had to be reconnected ?

Is the alarm like the one pictured and discussed in this thread?

no not that alarm mine has 5 pins & a TUV sticker on it

Dunno but maybe it's normal for the alarm to sound when you disconnect and replace the battery, cause the bike doesn't know if you're the owner or a thief. If you put the key in or turn it, that might turn it off.

If it has a TuV sticker on it, then it has been approved in Germany.  Would this be a Euro Delivery bike, like mine is?

thomo wrote:no not that alarm mine has 5 pins & a TUV sticker on it

Please post some photos of the connectors and the unit itself. Photo posting instructions are in the Forum Functionality section.

daveyson wrote:Dunno but maybe it's normal for the alarm to sound when you disconnect and replace the battery, cause the bike doesn't know if you're the owner or a thief. If you put the key in or turn it, that might turn it off.

I've tried the alarm key doesn't seem to turn alarm off 
I think the internal 4.8v off the alarm is cactus

Ay thomo

Does it look like this:


If so I'm gunna guess the button through the lid lifts up when you raise the seat, setting off the alarm. Then you wouldn't be able to turn it off by lowering the seat (or maybe even the key) cause that would make it too easy for a thief. 

If the seat is up when you install the battery, that might be the problem, like maybe you can't turn it off while the seat is up, or turn the key (probably anti clockwise) with the button pressed, or something like that. Maybe connect the battery earth with the seat down.

Dunno if the sound is from the alarm unit or the bike horns, or if the horn works with the alarm removed.

daveyson wrote:Ay thomo

Does it look like this:


If so I'm gunna guess the button through the lid lifts up when you raise the seat, setting off the alarm. Then you wouldn't be able to turn it off by lowering the seat (or maybe even the key) cause that would make it too easy for a thief. 

If the seat is up when you install the battery, that might be the problem, like maybe you can't turn it off while the seat is up, or turn the key (probably anti clockwise) with the button pressed, or something like that. Maybe connect the battery earth with the seat down.

Dunno if the sound is from the alarm unit or the bike horns, or if the horn works with the alarm removed.

yep thats the one 
not had a chance to look at it lately but will do this week 
i found a charging lead in the tool compartment tried connecting that no luck might see what happens if i put voltage into the internal battery