Working on Kay today, I thought I'd look inside the front master cylinder. I found very little fluid and thought better pull this a part. The rubber boot at the plunger part was wetish so I'm thinking this is were the fluid has gone. The sight glass is also missing and an aluminium plug complete with O ring and bolt have been installed though the sight glass hole. Bore looks good and I'll up load some fotos later. Looking on line I think I have found valve for money a rebuild kit. 

https://www.beemerboneyard.com/32722332037pk.html
                                      or
https://www.kmodelbeamerbits.com.au/bmwk-seriesshop.html#!/K1-K100RS-16v-K1100RS-LT-Front-Brake-M-C-Repair-Kit-Piston-WD-S1/p/84409309/category=23450038

I was surprised how complex the whole unit is put together. Once a part and semi cleaned all parts went into the ultra-sonic bath for 30mins.
I was shocked to see the twist grip body had a small crack in it's housing, I lined this up with the twist grip and I think it could be caused by snapping the twist grip? 


Has anyone else found this to be a problem?

I've seen a fair number of those and never seen one cracked like that.

That's been hit hard with something from the inside. The giveaway is that when you sanded the paint back, it only really cleaned one side. The other side is depressed (just like you are ATM I'd guess! ). When did it happen? Odds are when the PO knocked out the sight glass.

Depressed! I haven't been out to the shed since I posted the pics.
I'm not sure whether to try and fix it, or buy a secondhand one. I was thinking of drilling little divots in the crack and then use a small G clamp to bring it back in line with the other half and weld it.
It will be my first try at using aluminium welding sticks, so I could learn a new skill here.
Talking about learning what does PO mean?

PO = previous owner
Easyweld = not good enough for that job. It won't hold the 'springback' pressure when you release the clamp
Ally weld = a fine line of about 20 degreesF between ready to weld and complete meltdown. Definately a specialist job because it will need pre-heating.

Guess that just leaves the secondhand one... OTOH, I'd say that one is still usable. The cracked area is not load-bearing.

Dai wrote:PO = previous owner

Doh, I thought it was something nasty......

Yeah second hand will be the go.....  I'll keep looking at things and hope there's nothing else the PO did that will bite me.

I'll have a hunt around the cave tomorrow, I may have one of those that isn't cracked.

RicK G wrote:I'll have a hunt around the cave tomorrow, I may have one of those that isn't cracked.

That would be very beautiful RicK G

Hi Svenok, I'll have a look around for one. I'm pretty sure I have one. Cheers Tom

Tom FKR wrote:Hi Svenok, I'll have a look around for one. I'm pretty sure I have one. Cheers Tom

Guys I'm very grateful, thanks for looking.

Apparently not Sven, the bit I was thinking off was for a K1100

RicK G wrote:Apparently not Sven, the bit I was thinking off was for a K1100

RicK G
It's the thought that counts mate. All good

Rick G, that VIN number says 09/90 manufacture and RealOEM says 20mm front master so wouldn't that be the 4V with common part number to K1100 models?

Methinks that you are right when thinking it is a K1100 part.

Cheers

Guys I'm sure when I measured the piston it was 19.83mm so I'm leaning towards the 20mm repair kit.

That's my two cents worth.

I'll stick my brain back in and have another good look or as Margie is wont to say a woman's look

Being Saturday I thought I'd do a bit more with "Kay" and see why the ABS supposedly doesn't work. Since it was already off the bike I removed the screws out of the black box and exposed it's brain. I was looking for water damage as suggested in post within k100 community.I can see a lot of corrosion on some of the "pic" chips and wonder if this could be a sign of water ingress at some stage.