Author Topic: BMW K75RT Ultima Restoration  (Read 5930 times)

Offline Wollyjumperuk

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  • Posts: 48
BMW K75RT Ultima Restoration: Seat Lock
« Reply #50 on: October 25, 2018, 01:53:32 PM »
As I was working on the back end, the seat lock was next in line, so that was pulled out of the box and put on the bench and stripped down ...

... to allow the parts to be cleaned up with Muc-Off motorcycle cleaner and the helmet lock catch polished up. This catch did show some corrosion on the chome plate, but it wasn't significant enough at this stage to justify replacement, so just the cleaning for this time.

The smooth head square cap bolts had previously been badly painted, so this was stripped off and the heads repainted with layers of Autotek Etch Primer, Halfords Gloss Black Enamel and Halfords Clear Enamel Lacquer before being allowed to cure.

The fittings were bought back together...

... before the lock unit was offered up and mounted to the bike...

... with the helmet catch and the seat lock mechanisms greased as well as the helmet catch with WD-40'ed return spring added to complete the job.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

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  • Posts: 48
BMW K75RT Ultima Restoration: Front Brake
« Reply #51 on: November 10, 2018, 01:44:26 PM »
With the back end of the bike starting to look good, the last of the systems running the length of the bike is the front brakes.

But, as the handlebars are not ready, this bit will be left for now.

So, everything was pulled together and the order of work decided, starting with the brake calipers, which were pulled out...

... the caps popped off and the pad pins drifted out and the pinch bolts, with a fair amount of effort, unwound...

... and put in the metal recycling box, these are definitely going to be replaced!

The ABS sensor was the next bit to take off, did it want to play ball? Did it hell! So, after heating and penetrating oil the damn thing still wouldn't budge ... so drilling out is the way forward to reveal some corrosion welding the bolts into place.

The sensor was also corroded in, meaning this needed to be wedged out with a screwdriver...

... to reveal the size of the tidy-up job here! The remaining studs were punched and drilled out to 5mm before a M6 tap was wound through to allow the sensor to be reattached later.

From riding the bike to the workshop, I know the brakes are good, so there is no need to go any deeper than this, so everything for each caliper was laid out and the halves of each caliper cleaned up, showing just how bad the cosmetic condition of the caliper was...

... given this condition, the paintwork was scuffed up, dust seals removed, mating faces masked up and the pistons masked up before building up thin coats of K2 Gloss Black Brake Caliper paint giving this plenty of time to cure (about 3 weeks while I was away for work) , before the o-ring was replace and both halves bolted back together, allowing the other bits to be lined up for cleaning and refitting...

... which went without incident...

... ready for the calipers to be reinstalled on the bike...

... allowing the pinch bolts to be torqued up (not that I could find a setting, so whatever felt right really - if there is any evidence of leaking when I bleed these, they'll be nipped up) and finishing the calipers, although the mounts have not been tightened as these will have to be moved to allow the front wheel to be removed for sorting later.

It's worth nothing here that due to high tensile strength bolts being removed, there were replaced with the same specification and not straight stainless steel bolts.

Next were the 2 flexible lines in the system, both of which showed corrosion on the ends...

... so both of the lines had both ends fitted with bolts and washers to protect the mating faces and the rubber portions masked off, allowing the build up of thin coats of Motip Silver Brake Caliper paint...

... and allowed to cure, before being put aside until the rest of the system is ready to be fitted.

Next on the list was the ABS pump, which was in a bit of a sorry state...

... so this was taken back with a wire wheel attachment on a drill to remove the loose material, but I found so much under-paint corrosion that across the majority of the pump it needed to be taken back to bare metal before the cable and brake fluid channels were masked off and the body coated with Autotek Etch Primer, Halfords Gloss Black Enamel and Halfords Clear Lacquer Enamel, before being set aside to cure and allow it to be mounted...

... complete with bleed nipple.

The final target for cleaning up were the fixed lines, so these were put on the bench, cleaned up and laid out on the bike...

... and the scale of the task dawn on me, I should have run these lines before I fitted the wiring loom back in, this will require a lot of wiggling and swearing!

So, the lines were fed through from the front of the bike, wiggling, shoving, pushing, adjusting and pulling one of the lines at a time until both were fed through and bolted into the ABS pump. I must admit, it would be so much easier if I'd not had the fusebox in at the time.

But it allowed the fixed lines for the calipers to be reinstalled alongside the flexible lines...

... before all the fittings were torqued down.

So the last bit to do is the earthing lead on the ABS pump, which had corroded through and dropped off as it was taken off the bike. But a new connector was found for the end, the wire was stripped back, continuity checked, new end attached, continuity checked again and bolted between the ABS pump and onto the top bolt of the footrest, between the plate and the gearbox.

Finally the continuity was checked again...

... and found to be good - finishing that job, with the master cylinder being completed as part of the handlebars and bleeding down as part of the commissioning later.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

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  • Posts: 48
BMW K75RT Ultima Restoration: Radiator & Cooling
« Reply #52 on: November 20, 2018, 05:43:20 AM »
Next in line is the cooling system, given the water pump has previously been done, that means the radiator and hoses, so that was popped on the bench...

...the easiest bit to remove is the stub pipe which fits onto the crank case, so that was removed, the temperature sensor removed and the pipe popped into the vice...

... which was cleaned up with a wire brush attachment on a drill and the stub pipe masked up before being given a few coats of Plastikote Aluminium Engine Enamel, allowed to dry and the masking removed...

... and set aside to cure.

So, back to the radiator assembly, the hoses were removed and put to one side, allowing direct access to the fan, which was definitely 'firmly' attached - with 2 seized bolts which were cleaned up with a wire brush and the edges of the heads cleared of corrosion with a pick tool before being treated with penetrating fluid on front and rear...

... and left to soak for a while, say time enough for a couple of cups of tea!

The bolts were tried again, but no movement was forthcoming. So a little heat was added to gently warm the bolts and the clips they bolt into, gentle because the proximity to the radiator...

... which, after a fair amount of time, allowed the bolt to be eased out and left me with a loose fan, but it needed some cleaning up after that!

And onto sorting out the state of the radiator parts, starting with the radiator itself, which wasn't in the best of conditions cosmetically...

... but the cooling surfaces and internal pipe work all looked good and there were no leaks on the ride home.

As nothing was fundamentally wrong, the radiator was cleaned with a rag and WD-40, the blistered and flaking paint removed with the help of a wire brush and a pointy tool, taking care not to damage the internals before being painted with cylinder block paint...

... and set aside to cure off.

While waiting for that, the thermostat and cap were next up and as these are known to be good, these were cleaned up and the thermostat replaced in the radiator...

... followed by the cap returning the radiator to one piece.

Next up is the bottom mount which was cleaned up with a wire brush drill attachment and the elbow grease of a good friend, so it was ready for painting.

The mount was treated to layers of Autotek Etch Primer, Halfords Gloss Black Enamel and Halfords Clear Enamel Lacquer and left to cure off.

Meanwhile, attention was turned to the cooling fan, which was tested for function by jumping it across the battery...

... and it worked faultlessly.

The balance weight was removed, the location marked and the weight was cleaned up before a couple of coats of Hammerite Smooth Silver and set aside to cure.

The fan itself was cleaned up with a rag and WD-40 and the balance weight replaced...

... meaning the fan is done!

The stub pipe was refitted with the temperature sensor, with the copper washer replaced and the threads smeared with gasket sealant and the unit was fitted with a new o-ring and mounted onto the crankcase so it's ready for the rest of the cooling system.

The radiator assembly was put back together and loosely mounted on it's bottom mounts...

... as an offering up to make sure everything is where it needs to be (and proving I may need to visit the routing of the front brake fixed pipework, but I'll sort that later).

With that done, all the hoses were pulled together and cleaned up with WD-40 before the hoses on the stub pipe were reconnected...

... before the radiator could be remounted and the remainder of the hoses reconnected.

Next step was the expansion bottle, which was grabbed from the ever-shrinking parts pile which was cleaned up and mounted back into the frame...

... which then allowed the air intake ducting to be replaced...

... finishing both the radiator work and the airbox.

As usual, the system will be commissioned later.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

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  • Posts: 48
BMW K75RT Ultima Restoration: Bodywork Mounts
« Reply #53 on: December 09, 2018, 03:27:51 AM »
As some of the electricals and control cables need to be run through the front bodywork mounting, it seemed reasonable to the mounts done next.

Starting with the front mount, this was pulled together and the rust stripped off, with the remaining paint prepared by roughing up with 600 grit wet & dry paper...

... before Autotek Etch Primer was applied before coats of Hycote Gloss Black and Halfords Clear Enamel Lacquer and set aside to cure.

Once cured, it was bolted back onto the headstock...

... allowing the rubber grommets to be refitted ready and cables properly run.

Onto the remaining bodywork mounts, these were grabbed together...

... and had all surface corrosion and dirt removed with a wire brush drill attachment these were then treated to a good number of coats of Hammerite Smooth Silver...

... and set aside to cure off.

The mounts were then rebuilt with the original bolts, rubber grommets and mushroom washers before being mounted onto the fixing points on the bike...

... with one 1 mount requiring the radiator filler cap to be moved to allow it to fit.

To finish the job, the relay mounted on the front bracket was cleaned up, refitted and connected up to the wiring loom.

Onto the next job!

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline natalena

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  • Posts: 230
Re: BMW K75RT Ultima Restoration
« Reply #54 on: December 09, 2018, 08:13:55 AM »
Fantastic, methodical progress. Well done, and has inspired me to work on some fiddly bits as the temps drop below 3c here (seat lock assembly for certain.) Cheers
  • East of Joshua Tree
  • 1987 K75s #0919
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Offline Barry in IN

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Re: BMW K75RT Ultima Restoration
« Reply #55 on: December 09, 2018, 01:22:59 PM »
This is great to see.  It’s the kind of “build” I can really appreciate. 
  • Indiana
  • 1992 K75S Lili Von Shtuppe
A pox on cafe “builders”
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Offline Wollyjumperuk

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BMW K75RT Ultima Restoration: Handlebars & Controls
« Reply #56 on: January 01, 2019, 10:41:10 AM »
Getting the bike on and off the lift is a bit of a pain at the moment, so handlebars should help with that.

These were grabbed and popped on the bench and stripped to the bare handlebars...

... from here the bars were stripped back to bare metal, due to the rust seen on the clutch lever side of the handlebars, before being treated to Autotek Etch Primer, Halfords Gloss Black Enamel and Halfords Clear Enamel Lacquer and allowed to cure.

Once cured off, a length of fairly stiff electrical cable was fed from the centre hole in the handlebars to one end, before the remained was looped around the handlebars and then fed through to the other end...

.. to allow the cables for the heated grips to be pulled through later on.

This was then mounted onto the top yoke of the bike, adjusted (for now) and torqued down.

With that done onto the controls, which were popped onto the bench in turn and stripped down. The front brake master cylinder was inspected but it will stay in situ, rather than risking damage by stripping it down when I know it works well.

The adjustable parts, such as the front brake light grub screw were measured so that when these are replaced, they can accurately be reset and minor adjustment undertaken from there.

Once stripped down, this left me with 2 piles of bits...

... things that need cleaning and degreasing and those bits which are in good condition.

The bits that needed cleaning were soaked in Muc-Off Motorcycle Cleaner while the electrical items were tested for function and the screw threads cleaned up by running them through a dye.

With that done, and the parts continuing to soak, onto the electrical switchgrear elements of the handlebar controls...

... these are known to work, so no further stripping down required. But the controls were grubby, so using a rag with a small amount of WD-40 these were cleaned up. The thing that struck me here was that the markings on the controls were very faded, in no way a problem to function but gives me some research to do to see if these can be replaced.

Once done, the wiring for the controls was fed through the front of the bike and connected up ready for the remainder of the parts, once completed.

Next up was the central handlebar controls which were broken down into it's component parts...

... and the mount was cleaned up with WD-40 on a rag  leaving the next step as the ignition barrel.

On removal the tab retaining this dropped out, it would explain why the barrel was partially push back into the dash, so by using a hot knife this was plastic welded back on to the stump which allowed the barrel to be checked for electrical operation with a multimeter before being refitted into the housing.

Each of the switches on the housing was tested electrically and cleaned before being refitted into the housing.

The hazard light switch was found to have corroded electrical connections and a broken wire on further investigation the internal connections were also corroded...

... so these were cleaned up with a little sandpaper and electrical contact cleaner before the back of the switch was refitted.

The external connections were de-soldered, the wires stripped back to remove the corrosion and the contacts cleaned up with a wire brush. The wires were then soldered back onto the switch and tested and found to now be operational.

his allowed the central control panel to be rebuilt and bolted back onto the bike...

... allowing me to move onto the handlebar controls, which required the clutch sensor to be removed with a box spanner...

... unfortunately this did call for the cable to be cut, but this will be reconnected once everything was done.

With the control parts stripped (yes I gave in and removed the front brake master cylinder), soaked and degreased, the parts that then required painting were stripped using Rustoleum No.1 Green Paint Stripper before these were given coats of Autotek Etch Primer, Halfords Gloss Black Enamel and Halfords Clear Enamel Lacquer...

...and were allowed to cure off before reassembly commenced with both sets of controls being as built up as possible before even looking at the bike.

While everything was being added to the handlebars, the wires for the heated grips were taped to the wires that had been previously threaded through...

... allowing the wire to be pulled through to the exit hole in he centre of the handlebars, and the grip fitted to the bar...

... so the heated grip wiring could be soldered back together and connected up, alongside the wiring for the clutch, brake and sundry dash switches.

Following this, the choke, throttle and clutch lines were run and hooked up, just leaving the flexible front brake line, which was connected to the fixed line and connected up tot he master cylinder.

Things like the clutch adjustment and a decision on if I'm going to take a look at re-marking the handlebar controls will happen with the commissioning and finishing touches respectively.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 48
BMW K75RT Ultima Restoration: Clocks & Horns
« Reply #57 on: January 01, 2019, 10:50:49 AM »
With the front end taking shape slowly, various work commitments and seeing family slowing work down (but not is a bad way - just in case my wife reads this), it was time to move onto the clocks.

Thankfully I'd kept the clocks in one piece while the bike was disassembled, as I knew these worked and didn't suffer from fogging seen on some K75's, so a straight re-fit, happy times here! With a spring in my step, at the thought of an easy job, I grabbed the clocks and popped them on the bench giving the clear plastic a clean with a dry rag and the black plastic a wipe with a rag just dampened with WD-40, but something didn't look right...

... it seems when taking this off the bike, I flipped the bracket around and refitted it, so that was quickly rectified (still with a spring in my step!) before the bolt holes were cleared up with a bolt and the tired looking bots replaced with stainless steel upgrades.

But, I went to mount the clocks, something else didn't look right...

that rubber seal shouldn't look like that. So the back of the clocks were popped off to find that at some point in history the clocks had been apart (probably to replace a bulb), the seal had been allowed to fold over on refitting. This was straightened out and the back screwed back onto the clocks, finally now ready for bolting back onto the bike!

The clocks were offered up, wiring from the handlebar controls directed through the curve (but not the hole) in the bracket, and the electrical connector for the clocks pushed into place...

... and secured with a small bolt into the back of the housing.

Leaving the handlebar based items pretty much completed...

... until I change my mind about something anyway!

While I was on a roll, I grabbed the horns...

... and as these worked well before the bike was disassembled, they were cleaned up, bolted back into place and the wiring reattached...

... completing 2 jobs in one here.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 48
BMW K75RT Ultima Restoration CDI Unit & Tray
« Reply #58 on: January 27, 2019, 10:38:12 AM »
With the bike really taking shape, t was time to get the last of the big electrical bits done, thankfully an easy fitting of the CDI and it's housing

So, the lump was popped onto the bench...

... to allow it to be stripped down to components.

The rubber mounts wiped clean with WD-40 and fitted onto the frame the tray was also wiped clean with a cloth dampened with WD-40 (you'd be surprised how little I get through on a project), and slotted onto the mounts...

... this allowed the CDI, after a wipe over, to be slotted in on it's rubber feet and secured with the pin through the rubber Bush on the far side...

… to keep it in place - quite good little fixing method this, it's clear a lot of thought has been put into the bike's design, shame about the routing of some of the wiring and control lines!

From there, the electrical connection was made...

… and the cover wiped clean and replaced before the top cover was similarly treated...

… and closed to finish the job! I love these quick simple ones!

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline Wollyjumperuk

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  • Posts: 48
BMW K75RT Ultima Restoration: Clutch Adjustment Saga
« Reply #59 on: February 03, 2019, 03:45:26 PM »
With everything looking like it should do, it looks like it’s time to adjust up that clutch and make starting her up a step closer!

So to start the free distance on the gearbox end of the clutch cable was measured from the metal sleeve end to the barrel in the actuation arm and adjusted ~75mm…

… as suggested by the Haynes and owners manuals, and the rubber boot was slid back up the cable to cover the metal end of the sleeve.

On the actuation adjuster, the 13mm lock nut was backed off and the procedure followed from the Haynes manual, backing out the bolt with the aid of a 10mm spanner by about 2 turn – or until it moves freely before being wound back in until some resistance is felt and the lock nut nipped up.

All looked good, so before saying the job was done, I held the clutch handlebar lever in with a clamp, selected first and spun the back wheel – clunk and the back wheel locked up. Trying second – clunk and the back wheel locked up, and similar in all other gears bar 5th … something really not right here.

So I put the garage to bed for the night and gave this some good thought over a beer, well a coffee, well a glass of water – anyway, the options on issues were (starting at the cheapest and easiest to sort out:
>Clutch thrust bearing (a little bit of play, but not concerning when inspected before)
>Clutch plates failing to disengage (again OK when inspected before, but something may be misaligned on reassembly)
>Gearbox fault (the most annoying to sort out and the previous inspection of the gearbox, which incidentally was only a condition check and nothing was taken out of the box, was the only time in history I’ve purposefully looked into a gearbox)

I guess it was start at the top of the list and work my way down it! The clutch cable was released again and the actuation arm moved out of the way to allow the clip, boot and spring to be removed from the rear of the gearbox before the piston and trust bearing were removed and play checked again…

… as seen before, there was a small amount of play – but as a problem was evident, this was replaced with a good condition used part with no play and the clutch actuation was rebuilt, with cable reattached.

The box was put back into first and the rear wheel spun – clunk. Spiffing, but at least that is now known to be good.

The next option was the clutch spring plate itself, to get to this, the entire back end of the drive train needs to be removed and the bike raised up off of the main stand, allowing a stack of wooden blocks to be placed under the engine block and an axle stand positioned under the front of the engine (for stability rather than load bearing)...

… allowing the bottle jack to be removed before the stands were removed and the bottom left and top right gearbox to bell-housing bolts removed. To replace these, 2 guide rods were made from 2 ~2 1/2" M8 bolts with large unthreaded portions with the heads taken off with a grinder. These are to make alignment of the gearbox input shaft and clutch push rod much easier, preventing damage to the splines, moving of the clutch alignment or bending of the push rod when removing and replacing the gearbox.

The guides were threaded in and the wooden block support checked, once I was happy all was ready to go and the bike was stable (or at least as stable as it was on the main stand before), all the remaining gearbox mounting bolts were removed from the bell-housing and the frame and the gearbox slid back on the guides (the actuation rod pulled out of the spring plate and into the gearbox) and then lifted away, exposing the clutch which was removed to allow the spring plate to be checked (which was fine) and all the surfaces to be cleaned up, as I was here anyway.

Everything was rebuilt, everything being torqued up and re-greased as appropriate, to the point of the gearbox being popped back on, clutch actuation reassembled and the drive shaft attached, first gear was selected, the clutch lever clamped in and the drive shaft rotated - clunk. Oh the deep joy that ran through my being, or extreme frustration (I am sure you can correctly select which one!).

As I had daylight left the gearbox was removed again and popped on the bench, allowing the gearbox to be cracked open and the problem was fairly quickly seen, I must have either aggravated (i.e. moved further out of alignment) or caused myself, one of the gear selector fork shafts to have pulled away from the selector drum...

at least a problem was identified. The selector forks were realigned, ensuring the selector forks were sat in the drum...

... before the front cover was replaced and bolted down, following the process used previously. The gearbox turned freely, so that a problem sorted, this was then popped back onto the guides and slotted forwards onto the clutch. The clutch actuation was reinstated and the gearbox was rotated through the gears again, with the clutch lever held in …. the result: a resounding CLUNK, but from a different location to before - you can't imagine how annoyed I was. This means I must have a remaining issue with the clutch - as the only bit I wasn't sure of was the alignment, I wanted to start there.

I did a little more research and from Motorbrick (thank you Alphadoc), it looks like a 1/2" socket for a 3/8" drive would fit over the push rod, work well and save buying the BMW tool for a one-time use.

To align the clutch I fitted the wire ring and the spring plate, using the push rod to hold this in place, followed by the forward plate, before the 1/2" socket was added to the push rod and the friction plate mounted, with the rearward plate mounted and bolted into place...

torquing up to 22Nm, to complete the mounting of the clutch, so much easier with the alignment technique!

The 1/2" socket and push rod were removed, the push rod pushed back into the gearbox input shaft and the gearbox mounted on the guides fitted earlier. The gearbox was slid forward and wiggled (quite a lot), but once the splines were aligned it slid home, allowing 4 of the gearbox mounting bolts to be fitted to prevent movement, the actuation was reinstated (less the rubber boot and clamp) and driveshaft added...

... to all the clutch disengagement to be checked and ... success! 1 gearbox fault and 2 clutch faults sorted - I was rather happy, it's fair to say, so a cup of tea to celebrate.

With this sorted, all the rear of the bike removed earlier was reinstated, meaning I was back were I started, less 3 faults.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see

Offline KosmicK1100

  • Motobrick Curious
  • Posts: 20
Re: BMW K75RT Ultima Restoration
« Reply #60 on: February 22, 2019, 01:23:46 PM »
Wow! You are super-human for restoring your K75 without using a media blaster! Quite a muscle workout, using a wire wheel! On the plus side, you don't have the concerns of media blast contamination to deal with.
So refreshing to see there are humans willing to undertake such a huge project. Thank you for sharing your work!
  • France, Germany
  • K1100RS
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Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 48
BMW K75RT Ultima Restoration: Mechanical Commissioning
« Reply #61 on: March 09, 2019, 06:16:36 PM »
With the gearbox/clutch issue sorted, it was time to get commissioning, starting by chucking the batter on charge for the duration and the earth cable from the front earth mount to the gearbox and gearbox to battery cables added to the earthing point on the gearbox...

… but the bolt looked a bit past it, so this was replaced with a new alternative. The battery charger was then attached for the duration, to ensure it was ready to go.

From there I started with the bevel box, the oil for which I had already got, FUCHS 80W-90 gear oil.

The drain plug torque was checked and the filler cap removed to allow the oil to be added up to the bottom of the threads of the filler, using about 260ml...

… the bevel box was rotated, with the gearbox in neutral, and the level checked before the filler cap replaced and torqued up. It's worth mentioning here that I cut a slot out of the funnel I use to allow the end to be drawn round on itself and fit into the smaller filler hold on the bevel box.

For the gearbox oil, the drain plug torque was checked, filler removed and the same FUCHS 80W-90 gear oil was used, using about 875ml of oil to reach the mark on the dipstick (tool kit C-spanner)...

… the gearbox rotated and run through the gears while rotating the back wheel by hand. The level was checked again and the cap fitted and torqued down.

And moving forward, it was time for engine oil, deciding to go with FUCHS Semi-Synthetic 10W-40 as it gave the greatest temperature window for operation across the temperatures usually seen in the UK.

As before, the drain plug torque was checked, the filler cap removed and the oil poured in to a good volume in the sump and the engine turned by hand before topping up again and replacing the filler cap replaced.

The spark plugs were next in line, these were taken out, cleaned up with a wire brush and the gap checked with a feeler gauge to ensure they are within service tolerance before refitting and the HT leads reattached.

I managed to get myself a replacement sticker for the coil pack, so I removed the cover for the coils to expose the damaged sticker cleaned up the coil and fitted the new sticker...

… unfortunately not a match, but it conveys the warning it needs to!

So, moving onto the rear brake, everything was wrapped in rags to protect it from brake fluid the reservoir was topped up, clear tube and pot connected to the nipple and the bleeding began from the ABS Pump, slightly applying the rear brake, opening the bleed nipple, pushing the foot brake through it's travel, closing the blood nipple and releasing the rear brake - bleeding the ABS pump before moving onto the rear caliper and repeating the operation.

Despite the bleeding, no brake pressure, so I repeated the bleeding process, and there was more air. As I got frustrated I shelved it for now and started on the front brakes - I'll come back to this once I've given it some thought.

The front brake reservoir was topped up and the brake lever tied up with an elastic band the nipple on the ABS pump was opened and allowed to gravity bleed (mainly so I could have a coffee!), this was repeated with the nipple on the left front caliper...

... and the bleed was done, pumped the brakes a few times and all the pads moved - so job done, or so I thought.

There was a puddle of brake fluid, I traced the leak back to the front brake master cylinder so the front brake reservoir was emptied, and the mess cleared up. I was somewhat disappointing as this was working perfectly before the strip down, maybe it was time for this to fail, maybe it just needs a good clean.

The front master cylinder was disassembled and cleaned before being reassembled and the unit held with the plunger up and a small amount of brake fluid added - and I waited for any bubbles to indicate a leak ... nothing, happy is not the word.

The fluid was all cleaned up, the master cylinder remounted and the reservoir was topped up, with the system bled back through to clear any air...

... once everything looked clear of bubbles, the front brake was pumped hard again and tied back to allow any remaining bubble-shaped gremlins to work their way back into the reservoir over night. The next morning the brake was lovely and firm and ready to stop.

With the front done, it was time to head back to the rear brake, it was time to give the system a thorough check through. The right hand side footrest hanger was removed and the rear brake master cylinder unbolted and the master cylinder was dismantled and all the internal components were cleaned up...

... as well as the bore, to ensure a good fit. The back end of the master cylinder looked a bit cruddy so it was cleaned up with 600 grit wet and dry paper with a similar treatment given to the mating faces of the brake line. Once done, the banjo bolt was reinserted and wound to the stop, before being taken out 1 turn and the exposed bolt length measured...

... and the thickness of the brake line end measured, this meant I needed 2.88mm of washers just to make up the space, let alone the crush distance, so I put a stack together which measured 3.25mm and applied these to the bolt...

... wound the banjo bolt back in to hold everything together for now. The right hand side footrest hanger was bolted back in place and the same banjo bolt check conducted on each fitting, cleaning up and adding washers where needed.

Following that, each bleed nipple was taken out and checked for seating marks before each seat and nipple was cleaned up with blue roll to remove any contamination and refitted.

The brake fluid reservoir was topped up with fresh fluid and the gravity feed line pinched, just above the master cylinder to bleed the air out of the feed line, save having to work that air all the way through the system.

The reservoir was again topped up and the bleed nipple on the caliper cracked open, allowing the system to gravity bleed once bled cleanly, I tied the brake lever down as with the front brake, to allow a reverse bleed to the reservoir overnight - in the morning solid and no leaks!

The next logical thing to do would be to add the coolant, so suitable coolant was diluted as per the instructions. Before I added any coolant, I went round the system and made sure all the hoses were tightly secured and the drain plug was torqued up. Once I was happy, the filler cap was removed and a funnel was popped into the filler hose, allowing coolant to be poured in and the air bubble out...

... slowly 2.5L of diluted coolant was added and another batch was made up before being slowly added to the point the coolant reached the top of the filler hose and once I was happy the system was as bled as it was going to be for now, the expansion tank was topped up. This allowed the filler caps to be replaced. A check under the bike confirmed no puddles of coolant - success for now!

This concludes the mechanical commissioning of the bike - bar the first run up to temperature which will have to wait until after the tank is back on.

It's also worth saying that once that run up to temperature has occurred, I'll again check all the levels of all the fluids to ensure everything is where it needs to be.

As always, if you'd like further details, please see
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
For more on my motorcycle projects - please see