Brought a K100 to tied me over the winter, whilst I sell my Guzzi (Don't ask me about Italian electrics, how can it go wrong sat in a dry garage for 6 weeks ?) and rebuild my 93 triumph Trident (just need some seals in the carbs and tank tap, looking to use a CRK cafe racer kit).

I wanted to try BMW as I fancy taking the barn door off as a winter hack run around, to do the odd rally.
I liked the K100's when they first came out but too ££££ for me at that time.
I got it for a song, but it has turned out to be a dog, despite a current recent MOT ....

1) Rear Brake, doesn;t work - brake cylinder looks locked in fully actuated position, so the pedal does nothing but rear wheel runs freely...
2) Front LH fork leaks. - going to try a plastic hook to see if I can clear any debris to stop (worked on the Guzzi), or I will replace seal..
3) Steering is stiff, but not constant...
4) seat doesn't seat, with the seat rod stuck in the lock. - can I release the lock to get the rod back out, as the keys don;t work ?

So item 3 - does the K100 have the steering damper in the head stock ?  If so can I just remove bolts to loosen , are they accessible behind the barn door, or do I have to remove it ??

I have only been able to ride it round the block, so I am not sure how it handles, it seemed ok, but now worried other problems could be lurking.

Of course other problems are lurking...  Have you seen this?

http://www.verrill.com/moto/newkbike.shtml

From your description it sounds like you've bought an RT.

Italian electrics = make a new wiring loom. Easy-peasy. It's one of the easier 1970s/80s wiring looms to modify and modernise. The problem with them is they were made to police spec; if a bit fails, pull it off and replace it. Unfortunately, that puts a LOT of failure points into the wiring.

1. Rear m/c = you're going to need to strip the footpeg hanger off the bike and find out why the pedal is locked down. The really good news is that the piston is held in the master cylinder with a small hex-head screw.  No trying to beat the sh!t out of the piston with a small screwdriver pushed into the outlet hole.

2. Leaky fork seal = replacement. The forks are not quite as easy to get apart as the Guzzi ones are and, unlike the Guzzi, they use the oil for damping as well as lubrication. Don't lose the circlip or spacer in the top of the sliders.

3. Steering = have you checked for brinneling (i.e. is there a noticeable click at the centre position)? The lower bearing is an interference fit, again, just like the Guzzi. However, the outer race is a complete bastard to get out because it is almost flush with the headstock tube.

4. Seat = I haven't met that problem Someone here will have though.

Welcome Noisey

Dai wrote: Of course other problems are lurking...  Have you seen this?

http://www.verrill.com/moto/newkbike.shtml

From your description it sounds like you've bought an RT.

Italian electrics = make a new wiring loom. Easy-peasy. It's one of the easier 1970s/80s wiring looms to modify and modernise. The problem with them is they were made to police spec; if a bit fails, pull it off and replace it. Unfortunately, that puts a LOT of failure points into the wiring.

1. Rear m/c = you're going to need to strip the footpeg hanger off the bike and find out why the pedal is locked down. The really good news is that the piston is held in the master cylinder with a small hex-head screw.  No trying to beat the sh!t out of the piston with a small screwdriver pushed into the outlet hole.

2. Leaky fork seal = replacement. The forks are not quite as easy to get apart as the Guzzi ones are and, unlike the Guzzi, they use the oil for damping as well as lubrication. Don't lose the circlip or spacer in the top of the sliders.

3. Steering = have you checked for brinneling (i.e. is there a noticeable click at the centre position)? The lower bearing is an interference fit, again, just like the Guzzi. However, the outer race is a complete bastard to get out because it is almost flush with the headstock tube.

4. Seat = I haven't met that problem Someone here will have though.

Yes, read the thread when I first came across the forum..

 Wiring loom !! ha ha, you are having a laugh.. I can barely keep the smoke in the wires, normally, let along re-wire... 
My mobile phone's, free head phones have bigger wires than a Guzzi...
I had to re-wire the start circuit to avoid key fob and starter switch, that was hard enough, just stripping the fairing off was an ordeal..
One of the reasons why I am selling it and looking at BMW..

I will strip out the brake first...

Fork seal shouldn't be too hard to do...

The steering is smooth, just gumming up, rather than catching on something / broken / worn bearing - which is why I wondered about the internal steering damper - or possibly solidified grease on the bearings...

Cheers.

Noisey

Rear master cylinder and brake removed...
Just as I suspected, the MOT is faked...
The brake hasn;t been bled.
Very little fluid came out of caliper, back down brake line (with bleed screw open)...
The Piston returned to it's un-applied, open position.

So I think there may either be a block in system / caliper pistons seized / or the previous owner just did nothing & got his mate to MOT it..

Going to order a new seal & gaiter , piston kit to replace the old, so I can clean internally...
I will remove the caliper and see if the pistons move back....

Don;t hold your breath...

Welcome Noisey, from just down the road.

Your details say this is a 1987 K100 - the foot peg plates look older. I can’t remember when BMW changed... I seem to recall that it was from 87 onwards. Exhaust is not standard either - so someone has done some upgrading.

Non ABS bike, so brakes a little more straight forward to fix. As Dai suggests, stripping down the rear master cylinders is worth doing. The calliper pistons can stick, but again not too hard a job to strip down - seal kits are readily available from the likes of James Sherlock, Motorworks, moto bins...etc.

Steering - no steering damper on K100. Usual failure is the grease in the headstock bearings is ignored for 30+ years and goes hard. This often leads to excessive bearing wear (get an notchy feel when move steering from one side to other and handle bar wobble when riding in straight line). Replacing the bearings needs all fairing removing (including the top bit with headlight in it). Not too difficult, but slide hammer is needed to get the outer bearing race out of the headstock. To do this job you remove the forks ...so might as well change the fork seals - you say the left hand one is leaking. Take care when removing the old seals, it is easy to damage the fork stantion.

These bikes like to be run - they do sulk when left to stand idle. She looks fairly clean and doesn’t look like a neglected, commuter hack. Most of the problems you mention are pretty routine maintenance items.

Other things to check - age of tyres, more than 4 years old and she’ll handle like a pig. If she has stood for a while, then you can have issues with crappy fuel that may cause all sorts of issues with tank, fuel pump and fuel hose seals etc.

Good luck!

When you take the caliper(s) off, check the state of the dust seal (the big seal that's immediately visible). If it's still sat down inside the recess (hasn't curled around the edges) then don't waste your money on a new overhaul kit as the main seal will almost certainly be still intact and working. Peel the dust seals off very carefully and take a wire brush to the caliper. If necessary, use a screwdriver to shift the crap in the corners. Wash, dry, check for crap that shouldn't be there and refit the dust seals.

OTOH, if the pistons won't return easily under dual thumb pressure or the dust seals look perished, consider overhauling the calipers. It's very rare that the main seal actually fails.

So..
Have a replacement M/C seal kit, original looks ok but rubber gaiter is shot.
Stripped rear caliper off and it all looks as good as gold.
I just don;t think they bled it through.
The front pad / push rubber of the M/C seal plunger had the head missing, when compared to the new seal kit.
Which explains the long travel on the pedal.

So tomorrow, will re-connect and bleed through.

So whilst stripping off the pedal mounts it exposed the swinging arm bearing carrier..
Yes, only 2 cap head screws - not 3...
The third has snapped off in the hole (by other people unknown / previous owner..)
After stripping the rear shock off, moving swinging arm up & down & checking for side play, it all seems fine and dandy...
So unless otherwise, will ignore it for another day !!

Seal kit has fixed rear brake - just needs a little adjustment, but will wait until the steering is sorted - so I can ride / adjust to suit...

Fairing off, to be honest I love it naked, will keep it that way - but not cafe racer, more retro...
Possibly with some straight bars (the BMW ones are nice & comfy but the rubber mounts are too soft).
Maybe a 7" headlamp with winkers and possibly a small cockpit style fairing.

Steering is stiffer than a vicars collar, so I need to strip it down further...