Author Topic: BMW K75RT Ultima Restoration  (Read 2810 times)

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima Restoration
« on: March 17, 2018, 02:34:29 PM »

Greetings  :mm ,


I have just moved on my last project and I would like to share with all of you my next project - a BMW K75RT Ultima.


As you may know, the Ultima is the final addition of these 3 cylinder engined motorbikes so beloved by police across the UK and Europe.


I picked this up from the father of a good friend, so I know the history and I know mechanically the bike is solid, so it is mainly cosmetic work I'm undertaking on this one.


For those of you interested, you can follow the progress of the restoration via MotorcycleProjects on Wordpress.com
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
Re: BMW K75RT Ultima Restoration
« Reply #1 on: March 17, 2018, 05:04:26 PM »
Looks like the link didn't work - here it is so you can go straight to it ... http://motorcycleprojects .wordpress.com
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
Re: BMW K75RT Ultima Restoration
« Reply #2 on: March 17, 2018, 06:28:44 PM »
Good thing I'm much better with suck - squeeze - bang - blow than micro-processors!


Let's try the link again ... [size=78%]https://motorcycleprojects.wordpress.com[/size]
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
Re: BMW K75RT Ultima Restoration
« Reply #3 on: March 18, 2018, 06:17:16 AM »
The father of a good friend has been considering selling his bike for a while and wanted to ensure it would go to someone who appreciated it. After a few cups of coffee and conversations about the bike over more than a year, and knowing the bike is pretty much there mechanically, it felt right to buy the bike and bring it back up to 100% cosmetically.

After getting the bike home, the bike had the once over to see what needed doing. After going through the history of the bike, it looks like the bike has always had genuine parts, so this will be continued as much as possible.

The initial to do list consists of:
>Sticky Rear Brake Light Switch
>tragkorb Hinges Cracked
>Dashboard Light
>Corroded Brake Line Fittings

>Paint Damage on Engine, Gearbox, Frame, Fork Stantion and Bevel Box

>Paint Damage on Rear Wheel

>Paint Damage on Bodywork

>Bubbling RHS Fairing Pocket Cover
>Corroded Nuts & Bolts


I try to take my time over projects, with these usually taking 18 months plus - so please watch this space for updates.
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5425
Re: BMW K75RT Ultima Restoration
« Reply #4 on: March 18, 2018, 06:59:02 AM »
Welcome, Wolly!

Your project is certain to be of interest here. Good luck with it.
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline The Mighty Gryphon

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  • Posts: 3767
Re: BMW K75RT Ultima Restoration
« Reply #5 on: March 18, 2018, 10:50:42 AM »
Looking at your list it sounds like a fairly straightforward and very satisfying project ahead for you. 

I like replacing nasty looking fasteners with stainless steel.  A lot of them for stuff that isn't heavily stressed where the original is M5 or M6(fairing panels, timing chain cover, etc.) can be the cheaper grade.  Just remember to reduce the torque on them by about 10% and use copper anti-seize.  I get mine in bulk fairly cheaply on eBay, or you can buy a complete kit that has just what you need.

With the age of the bike, you might want to replace the original brake lines with stainless steel braided along with new fittings.  Most of the places that sell the lines include new fittings.

A good inspection of the fuel lines and breather hose is in order.  You might just want to plan on replacing them if they don't look almost new.

If you can, see if you can find some S-100 for cleaning parts.  I have found that it is a super quick way to remove a lot of old dirt and grime and bring parts back to looking almost new.  When I am doing work on a bike, as soon as I remove something it goes to the laundry and gets a cleaning before I do anything else.  It's so pleasant to handle and work on clean parts.

Good luck with your project. 
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '92K100RS White, '94 K75S Dakar Yellow
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'94 K75S "Cheetos"
'91 K100RS "Moby Brick Too

Offline Wollyjumperuk

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  • Posts: 28
Re: BMW K75RT Ultima Restoration
« Reply #6 on: March 18, 2018, 10:58:23 AM »
Cheers for the advice Mighty Gryphon  :2thumbup: , it looks like we are thinking along the same lines regarding the brake lines, hoses and fixings.


I'll keep an eye out for S-100, I tend to clean parts before I do any work with them but if the S-100 can make cleaning easier, I'm all for it!
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

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  • Posts: 28
BMW K75RT Ultima: Bodywork Strip Down
« Reply #7 on: March 31, 2018, 02:09:25 AM »
With the bike safely in the garage and up on the ramp, it was time to remove the bodywork to see how bad the corrosion was on the frame, so see how far I'd have to get into the bike.


Starting from the back, all the parts were removed from the frame methodically, with all of the bolts replaced in the threads they came from ...

... all electrical connections marked before disconnection and photos taken of all the cable runs to ensure re-build as close as possible to original.


During the strip down only 2 fixings were so corroded that they had seized, unsurprisingly both of these were at the rear of the from, where these are directly exposed to the elements ...

... using PlusGas disassembly penetrant, a heat gun and (briefly) an impact driver, these were coaxed out - I can't stand sheered bolts and studs, so I tend to spend the time trying to coax these out. As you can see from the picture the corrosion to the back end of the frame was extensive, so I decided to remove the front fairings to see how far forward it goes and if I'd need to take the frame off the engine to sort the corrosion to my satisfaction.


The only challenge to removing the front fairing was getting the mirrors off the fairing. I did a fair amount of research into mirror removal, as the method to get these off seemed a bit brutal - at effectively hitting these with your palm from below, as hard as you can, to get these to 'pop off' ...

... in the end I used a large flat head screw-driver between the fairing and the mirror to 'pop' these off, fitting by fitting.


Following this the front end was pretty straight forward with all the fixings coming off cleanly, with no seized items at all and even a spare key fount cable-tied inside the front fairing! The nose fairing came off with the 6 bolts and the electrical connections were labelled and section taken off.
[/size]
I was expecting the corrosion to the rear, as the frame is really not protected from the dirt the rear wheel flings up, but there is evidence of corrosion all the way up to the front fairing sub-frame, not as bad as the rear of the bike, but enough to require the frame to come off of the engine to get it sorted.


For more information, please take a look at my bl[/size]og at https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline rbm

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  • Posts: 1776
Re: BMW K75RT Ultima: Bodywork Strip Down
« Reply #8 on: March 31, 2018, 04:58:58 PM »
The only challenge to removing the front fairing was getting the mirrors off the fairing. I did a fair amount of research into mirror removal, as the method to get these off seemed a bit brutal - at effectively hitting these with your palm from below, as hard as you can, to get these to 'pop off' ...

... in the end I used a large flat head screw-driver between the fairing and the mirror to 'pop' these off, fitting by fitting.
Don't sweat it.  These bikes are German. They appreciate a good slap now and then. :D
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/
2011 Moto Guzzi V7 Racer

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Frame & Engine Parting
« Reply #9 on: April 18, 2018, 05:57:10 PM »
With it clear that the frame of the bike was fairly corroded, it needed to come off to be sorted, so began the parting of the engine and the frame.


It started with an emptying of the coolant by disconnecting the hose at the lowest point and letting it drain before removing the radiator to reveal ...

... the corrosion at the front of the frame was worse than seen on the rest of the frame - supporting the decision to remove and treat the frame.


The brake system was bled down and the lines disconnected where they pass though the frame before the engine block was supported in preparation.


The front wheel was dropped out and the frame unbolted to allow the frame and forks to be removed in one section ...

... leaving the engine and transmission standing ...

... to be tackled next, alongside an oil leak from the rear of the gearbox, discovered just after the frame was released and removed.


For more information, please take a look at my bl[/size]og at https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Engine & Transmission Disassembly
« Reply #10 on: May 02, 2018, 05:41:17 PM »
The starting point was removal of the rear wheel and draining the oil out of the rear bevel box as I am going to change it anyway – I might as well get it as light to handle as possible! And it was just as well, as the oil that came out did look a little past it’s best.
[/size][/color]Following this the rear bevel box was unbolted and eased off the end of the swingarm and the drive shaft connector, bearing and smooth operation checked and all found to be very good with no play, so no further disassembly at this time here.[/font]
[/size][/color]Following the bevel box, the next component forward was the swing arm, the 2 stub axles were removed and this was eased away from the gearbox and slid off the drive shaft. The swingarm needs a good clean before an inspection can be properly done, so that’s for later.[/font]
[/size][/color]With the removal of the swingarm, support of the motor was somewhat lacking, so a few wooded chocks were put in to aid the bottle jack and the main stand to maintain stability …[/font]
[/size][/color][/font]
[/size][/color]… this support would later be supplemented with a ratchet strap over the garage roof beam to give a little reassurance.[/font]
[/size][/color]Looking toward removing the gearbox unit, it was clear the only other parts needing removing at this time was the alternator and the starter motor. These were both unbolted and eased out leaving a small pile of worn-off alternator cush drive rubber, so this goes on the replacement list too.[/font]
[/size][/color]The remainder of the wiring loom, coil packs, airbox assembly and throttle bodies were taken off with little effort, leaving the injectors to be eased out followed by the manifold stubs and coolant post.[/font]
[/size][/color]Unfortunately, both the front manifold stub and coolant post had seized bolts, 3 in total one sheered stud could be wound out by locking 2 nuts together on the stud (thankfully the thread was OK), and the stud wound out after some gentle heating and constant, steady application of pressure on the lower nut against the lock nut …[/font]
[/size][/color][/font]
[/size][/color]… I was not quite so lucky with the other 2 studs. Here starts on-off work on these over a 2 week period.[/font]
[/size][/color]After many attempts to remove, , these were ground flush, drilled and tapped before the replacement bolt was run into the hole – success![/font]
[/size][/color]With the inlet manifold done, it was time to move onto extracting the gearbox. As this would mean turning the engine onto it’s leading face, the oil filter was drained (by punching 2 holes in it so it could drain) and the engine flipped the stands removed and the gearbox bolts undone. To aid things, a ratchet strap was threaded through the swingarm mounting holes and the slack taken up. The gearbox was tapped round with a rubber mallet to get it moving before the ratchet was used…[/font]
[/size][/color][/font]
[/size][/color]… to lift the gearbox away.[/font]
[/size][/color]The last part of the disassembly was the removal of the exhaust headers. So the engine was rolled so it was upside-down and the exhaust header studs given a coat of PlusGas and left to soak overnight.[/font]
[/size][/color]Once soaked, the nuts were heated up to expand them off the studs but they won’t budge and we’re rounded due to corrosion. A nut splitter was used to deform the nuts and provide something to grip on and an easy out socket used this worked with just a few nuts having to be beaten round.[/font]
[/size][/color]With that done, the major disassembly is complete… time to start the process of rebuilding![/font]
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline johnny

  • TrailBrakingThrottleWhacker
  • ^ Quintessential Motobricker
  • Posts: 6120
  • Whacking...n...Chopping Sliding...n...High Siding
Re: BMW K75RT Ultima Restoration
« Reply #11 on: May 02, 2018, 08:30:28 PM »
greetings...

very interested in your renovation... however that is one f-ed up post... unreadable at best...

you outta getts some seperation in there...

j o
  • i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin...
:usa#1

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
Re: BMW K75RT Ultima Restoration
« Reply #12 on: May 03, 2018, 12:34:01 PM »
Yes, it is pretty shocking - unfortunately I failed to use the preview button and there does not seem to be a way to edit this once posted.


Just as well I'm better with metal than with silicone!


Please feel free to check out https://motorcycleprojects.wordpress.com/ for a cleaner version
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline thecableguy

  • ^ Proficient Motobricker
  • Posts: 114
Re: BMW K75RT Ultima Restoration
« Reply #13 on: May 03, 2018, 01:03:10 PM »
... there does not seem to be a way to edit this once posted.

Once you hit the magical number of posts you'll unlock the "Edit" feature.


(The number is 10. You're almost there...)
  • Madison, WI USA
  • 86 K100RT - Brünhild
...to make a long story short, use duct tape.

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Main & Side Stands
« Reply #14 on: May 12, 2018, 06:42:30 PM »
The stand assembly was clamped in the vice ready for the disassembly. Everything was undone and disassembled, the stubborn bolt was lubricated and heated and pressure kept on the bolt until it released.

All the loose bits were put in a bucket, part cleaner added and diluted and left the soak overnight. After soaking the water was definitely dirty and the parts vaguely cleaner!

With everything taken apart and spread out to check everything is here...

... and any parts damaged beyond use or repair were replaced.

The side stand - clutch interlock was particularly caked in road crud, so it went from fresh off the bike (top left) to being soaked in Muc-Off cleaner and being scrubbed (bottom left) degreased (bottom right) and polished up using Autosol Metal Polish, fine wire wool, soft cloth and a polishing mop on a drill (top right)...

... this was also done to the other required non-painted parts.

The stand mounting bracket and both stands were stripped back with a wire brush drill attachment removing all the old paint and corrosion before masking up, spring holders masked by using o-rings (as the springs will kill the paint anyway) and priming with 2 coats of Autotek Etch Primer, followed by 2 coats of Halfords Gloss Black Enamel (typically running out of paint half way through, so had to run and get some more) and finally 2 coats of Halfords Clear Enamel Lacquer. With 24 hours left between each change in paint and everything left to completely cure for a further week once completed.

Once cured, all the parts were pulled together and the stand assembly rebuilt...

... ready to be bolted back onto the gearbox.

N. B. The springs will be added once the stands are on the engine/transmission assembly for ease of leverage.
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

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  • Posts: 28
BMW K75RT Ultima: Gearbox, Engine & Stands
« Reply #15 on: May 29, 2018, 03:42:32 PM »
The engine and gearbox were cleaned up with Muc-Off motorcycle cleaner, elbow grease and a fair amount of soaking time!

On further research, it looks like the oil seen leaking from the clutch pushrod boot was to be expected when the plunger is removed. But that leak and the weep seen on the input side...

... coupled with the greasy residue in the clutch housing as well as the oily residue on the underside of the clutch housing seen during disassembly, I decided a new input shaft and clutch pushrod seal would be worth fitting as I was here anyway.

The input seal replacement was fairly straightforward (if long winded), consisting of popping the front cover, remembering to remove the neutral bolt, spring and ball bearing, and levering out the old seal...

... drifting out the seal plug for the neutral are and using an M8 bolt in the seal plug hole to hold this back, cleaning up and smearing a small amount of gasket sealant on the mating faces, ensuring all the shims are aligned and easing the cover back onto the locating pins and tapping into place with a mallet, before removing the M8 bolt to allow the neutral arm to return, refitting the ball bearing, spring and bolt ...

... and easing the new input seal over the input shaft and using a socket to seat this flush with the cover.

The clutch pushrod seal at the rear of the gearbox was a little more awkward, being a case of the seal that doesn't want to shift. I started with a small dentist style tool to get behind the seal, but this wouldn't budge (after an hour or so of gentle coaxing). While scratching my head, I decided on folding the metal part of the seal inward and across the hole for the pushrod. With that done, the pushrod was reinserted and gently tapped with a mallet, drifted the seal out.

The outside of the gearbox was given a stiff wire brushing, a wipe down to remove the loose stuff and a coat of engine paint (as it was the best match for the original I had)...


While I had the paint out, I thought I'd get the engine block ready for reassembly, with the areas needing attention were cleaned up with a wire brush and cellulose thinners before 2 coats of the engine enamel paint were applied and left to cure for 2 weeks (while I jumped on my Triumph and disappeared to Scotland... Well, it'd be rude to stand and stare at drying paint).

Once cured (and after the holiday), the clutch pushrod seal needed to be fitted, the gearbox was sat input side down, chocked up on wooden blocks, with the pushrod installed and the seal slid onto the pushrod and a deep 10mm socket used, with a rubber mallet, to push the seal into place. As I was trying to be gentle, drifting the seal in did take some time.

With all that done, it was time to mate the two parts!

The pushrod was used as a guide to slide the gearbox into place, before the lugs were used to locate the gearbox and the bolts installed and torqued down.
As I was here, I took the opportunity to install the stands...

... ready for the assembly to be flipped over so the engine casings can be worked on.

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Clutch Pushrod Arm
« Reply #16 on: June 02, 2018, 02:29:11 PM »
With the engine and gearbox back together, it was time for the clutch pushrod arm and refitting of the side stand interlock arm.

Starting with laying out of the parts for the pushrod arm assembly...

... everything was cleaned up, firstly by scrapping off the crud, then with liberal use of Muc-Off cleaner and a stiff brush.

The arm was then taken back to bare metal with a wire brush attachment on a drill, before Autotek Etch Primer, 2 coats of Hycote Stoneguard Black and a further 2 of Hycote Clear Lacquer before leaving to cure.

With that done, the slider, spring and boot were refitted to the... But it didn't look right. So the gearbox had to come back off and the pushrod removed, the slider, spring and boot refitted...

... the pushrod refitted before the gearbox was reattached to the engine. Probably should have read the Haynes manual before I started! Oh well, lesson learned.

The arm was greased and slid into place and the pin greased before being refitted, and the circlip sworn at until it was back on!
On the other end of the pin, the clutch interlock arm was fitted followed by the washer, circlip (more swearing) and the return spring. This was then mated to the push assembly on the side stand...

... and operation checked before moving on.

The stand bearings were greased via the nipples and spring grooves greased, before the excess was cleaned off.

The last stage was the side and main stand springs. Given I've hurt myself before with trying to use pliers for this, I ordered a spring puller tool (glorified hook with a handle).

Once the tool arrived the springs were pulled into position, so the whole assembly could then be turned over...

... ready to crack on with the swingarm!

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 3442
Re: BMW K75RT Ultima Restoration
« Reply #17 on: June 02, 2018, 03:18:57 PM »
While you are at this stage you might want to add a grease nipple to the clutch arm. It will give you the ability to push out the accumulated road crap. And it should help prolong the life of your clutch cable and your arm.
Regards Martin.
 [ Invalid Attachment ]
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline stokester

  • ^ Proficient Motobricker
  • Posts: 381
Re: BMW K75RT Ultima Restoration
« Reply #18 on: June 02, 2018, 05:01:53 PM »
Thanks for the updates, a very interesting project  :popcorm
  • Yorktown, Virginia
  • '94 K75S - '93 K75S - '91 R100RT - '78 R100S

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75 Ultima: Swingarm & Drive Shaft
« Reply #19 on: June 04, 2018, 03:54:41 PM »
Carrying on rearward of the gearbox, it was time for the swingarm and drive shaft.

As usual, all the parts were laid out…

… and everything got a good clean, before being inspected. Thankfully everything was found to be in good shape, so no replacements needed but the swingarm itself needed repainting.

So, as usual, this was prepared by remo in the loose material and keying the surface, primed with Autotek Etch Primer, top coated with Halfords Enamel Gloss Black (for the robustness of the enamel paint), finished with Halfords Enamel Clear Lacquer and left to cure for a few days.

Before all the bits were put back together…


… the rubber boot put back on the gearbox end of the swingarm and the retaining clip added (don’t try to put the clip in the boot first, it doesn’t work very well and cost me time trying to be clever!).

The gearbox output spline was greased… now there is a huge amount of debate here on what grease to use, for me it was a case of a good clean and a smear of general purpose or bearing grease if you have it, but the debate is to be had (see the threads on the rest of motobrick.com)… the swingarm was aligned until the boot popped into place and the sub axles slotted in…

… with the bevel box end supported with an axle stand.

The fixed stub axle was pushed all the way home before the bolts were torqued up, with the adjustable stub axle was wound all the way in to preload the bearings before being slackened off, torqued up, the locking nut applied and also torqued up.

With the gearbox output spline already lubricated, the universal joint and spline on the end of the drive shaft were cleaned and lubricated before being fitted via the swingarm.

Following this, I had a look around and discovered the boot of the clutch pushrod had split on refitting, so the clutch pushrod arm was removed to allow the boot to be removed, so a new one was ordered. And, with the pushrod arm off, I thought I’d take the advice from Martin (see above) and add a grease nipple here.


As always, if you'd like further details, please seehttps://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75 Ultima: Clutch Pushrod Arm (Grease Nipple Addition)
« Reply #20 on: June 07, 2018, 01:27:14 PM »
Taking the forum advice on motorbrick.com, and while the arm was off to replace the clutch pushrod boot, I took the opportunity to fit a grease nipple.

So, the first step was to measure where I wanted the nipple to be and mark that with a punch...

... the area masked up and a pilot hole drilled at 2.5mm diameter, which was then enlarged to 5mm diameter and tapped out to an M6 thread with a 1.0 pitch before the inside of the hole, as well as the shaft bore was cleaned out and the grease nipple fitted...

... the masking removed and was ready to go.

The replacement clutch pushrod boot was replaced, typically the bolt on the securing ring sheered so that was replaced, before the clutch pushrod arm refitted and greased via the new nipple and cleaned up...

... job done!


As always, if you'd like further details, please seehttps://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75 Ultima: Bevel Box
« Reply #21 on: June 08, 2018, 12:13:53 PM »
To finish off the back-end of the transmission, time to get the bevel box re-finished and fitted. The oil was drained out during the strip down, and will be put back in during the commissioning after all the cosmetic work is done.



Firstly the brake disk was taken off so the overall condition of the bevel box could be assessed. Fair to say that it really did need a new paint finish and the splines greasing up, other than that everything moved freely with no resistance - so no new bearings needed! Even more of a bonus was that there was no evidence of oil leaks, so all the seals were good.

To prepare the bevel box for painting each of the holes was plugged with blue roll, to prevent any loose crud getting into the oil chamber and causing damage and the bevel box was split by taking out the retaining bolts (popping it in a vice really helped here!) before using a bar between the box section around the drive input and the rear brake caliper mounts to ease the cover and internals away.

This showed the state of the internal seal and it's fair to say I was surprised the main seal wasn't leaking! Both the sealing face and recess of the main body, the sealing face of the cover as well as the channel for the main seal was corroded quite badly. So much so ...



... that the main seal had to be thrown away as the corrosion had pressed on the seal and caused a significant kink, meaning if the seal could be cleaned up, it was unlikely to give the best seal possible - so for a few £££ the seal would be replaced.

All of the corrosion was taken back, initially with a scraper before fine wet and dry sand paper to tidy the corroded areas. As much of the remaining oil in the bevel box was mopped up before the halves being placed to allow the oil to drain for a few days.

Once as much of the oil that was going to come out had come out, the process of masking up ready for paint preparation began. Starting with covering the internals attached to the bevel box cover followed by the outer seal, mating faces of the retaining bolt holes and the mating faces for the rear caliper being masked off ...



... ready for the worn paint work was removed back to bare metal where really bag and otherwise heavily scuffed to give a good key for the paint (with the back case treated in the same manner). A good smooth grade between the 2 areas was achieved with more wet and dry paper across the interfaces to remove any lip.

The 2 halves then had the usual 2 coats of Autotek Etch Primer, 2 coats of Halfords Enamel Gloss Black and 2 coats of Halfords Enamel Clear Lacquer and left to cure before being de-masked and brought back together with the other parts of the bevel box.



The new main seal was popped onto the bevel box cover the drive shaft and bevel box input splines were cleaned and lubricated up ...



... before the casing of the bevel box was bolted back onto the swing arm. The swingarm and bevel box were again supported on an axle stand with news paper on to protect the paint finish ...



... and allow support while the cover was replaced on the back casing. This was done by replacing 3 bolts equally spaced at every other hole and each tightened a turn at a time to ease the cover back on square. Once in, the other bolts were added and all bolts were torqued up ...



... before the cleaned filler and drain plugs (fitted with new copper washers), speedo drive, breather o-ring and cap as well as the nut for the suspension were put back onto the unit.

With that lot done , the gearbox was put into first to prevent the drive rotating and the rear brake disc was checked for warping (as this seems to be a common issue) and wear, both were fine and the disk was put back on the drive, bolts fitted with blue threadlock and torqued up.

For ease of moving the engine and transmission unit, the rear wheel with shim was temporarily bolted back on and hand tightened ...



... this made the engine and transmission unit move-able, just in case I needed the bike lift for anything else.

The next aim is to make the unit even more easy to move by getting to having a rolling frame and engine assembly - so onto the frame and I suspect a fair amount of wire wheel action to come!

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Alter-nator & Starter Motor
« Reply #22 on: July 01, 2018, 04:00:04 PM »
With the gearbox done, it was time to start bolting bits back to the top of it.

All the parts were laid out and the scrotator checked for free operation…



… which was the case, nice smooth rotation with no signs of bearing wear or restriction in rotation. From riding the bike home I know the unit is working well electrically, so the parts had a clean up as a unit (no need to dismantle a perfectly good item).

The seating was cleaned up to allow the unit to be refitted into the back of the bell housing.

The cush drive rubbers were refitted and offered up to the drive on the bell housing and wiggled to initiate engagement. Each of the bolts was given a few turns to hold the unit in place and then each of the 3 bolts had a turn added in a clockwise sequence to ease the cush drive onto the drive tabs.

With this eased into place, I tried to rotate the drive to check for any bagginess in the drive (well pushed my finger int he gap to try and try to rock the drive) and there was no wiggle at all, so the cush drive rubbers were a tight enough fit.



With the unit in, the bung in the starter motor insert was removed and the slot for the starter motor in the bell housing cleaned up ready for the motor.

Again, I knew this was good from the ride home, so only a double check was conducted with e feed directly from the battery and was found to be in good order.

Before refitting the o-ring was checked and it looked good, so this was smeared with some new engine oil to aid in fitting …



… before being slotted in and bolted down.

The continuity (resistance) between the starter motor and the gearbox/engine casing was checked to make sure of a good earth and ensure clean operation (especially as the gearbox mountings have been painted around) …



… and, again, this was found to be good to go.

With the electrical units fitted into the back of the bell housing ...



The electrical unit cover was a little broken, so a little super glue was used with the crack now only visible under quite a harsh light.

There were a few splodges of silver paint (similar to those seen on the gearbox and the frame), these were taken off with a blade held perpendicular to the surface.

The last step was the fitting of the cover, with shiny new stainless bolts replacing the corroded originals.a

A nice quick job to keep the momentum going while various items are being painted (asthe going seems rather slow, so I had to do something) …

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75 Ultima: Frame
« Reply #23 on: July 05, 2018, 02:34:42 PM »
So, the state of the frame was the reason I decided to go as far as I have into the bike rather than do a general re-fresh as was originally intended.

There was extensive surface corrosion on the rear end and the lower portion of the leading arms (where the radiator mounts) but fundamentally the frame was solid.

The frame was extensively stripped using a wire wheel attachment on the trusty old drill before the hard to reach stuff was chemically peeled, using No.1 Green Paint Stripper, leaving a pretty clean frame …



… with the tougher corrosion seen before, taken back with a lapping wheel on a grinder to a suitable painting surface.

With this done (and the headstock bearing falling apart when I took the yokes off) the headstock bearing races were pulled out and replacements ordered. The fluidbloc steering damper was masked into the headstock and not removed as this was in good condition and felt good when I was riding the bike back to the garage originally.

Due to the extent of the corrosion across the frame before I stripped it, and the use of a solid steel frame (which is not a light thing!), I took the step of Kurust-ing the entire frame …



… before sealing the frame to stop the chemical reaction by applying a coat of primer (as directed by the Kurust), returning to the trusty Hycote Red Primer to allow a clear indication of coating against the silver of the bare frame.

Following this, the entire frame was given another coat of primer before 2 colour coats and 2 of lacquer…



… before being left for a week to cure off.

The tired mounting bolts were replaced with stainless steel upgrades and used to secure the frame onto the engine and transmission assembly...



… and jobs a good ‘un!

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

Offline Wollyjumperuk

  • Motobrick Curious
  • Posts: 28
BMW K75RT Ultima: Yokes
« Reply #24 on: July 07, 2018, 12:28:49 PM »
With the frame ready for the yokes, it was time to get them done. The yokes were in fairly good condition but a few dings and a headstock bearing which fell apart on removal from the frame, this’ll get the works.



It’s worth nothing at this point these are marked as Showa yokes on both top and bottom yoke.

I wound the top yoke off the stem and drifted the upper headstock bearing holder out off the yoke and pushed this out until it was free with the upper headstock bearing drifted out of the holder via the 2 drift holes.

The lower bearing was drifted off the bottom yoke, using the 2 drift holes…



and that is everything disassembled.

The yokes themselves, as the largest components, were treated first. These were stripped by a wire brush attachment on a drill and masked up before being brought together with the front fork lowers and bridging piece ready for painting.

The top yoke, bottom yoke and handlebar clamps were masked up to prevent pain getting on the bearing surfaces for the forks and the handlebars, before they were treated to Autotek Etch Primer, Halfords Enamel Gloss Black and Halfords Enamel Clear Lacquer and put aside to cure.

While that was curing, the rest of the parts were inspected for corrosion …



… and cleaned up to allow reassembly…



With the headstock bearings falling apart when these were removed and therefore the bottom races removed from the headstock during the frame work, it was time to replace these ready for the yokes to go back on.

To achieve this a tool was made up from penny washers, standard washers, M8 threaded bar and a couple of nuts.

The headstock slots for the races were cleaned up and the new bottom races were pushed into the headstock and aligned by hand and measuring tool before the made up tool was added and would up to take out the slack …



… over the next hour or so, the nuts were tightened by 1/4 turn and the alignment checked, the tool repostioned, slack taken up and the tool tightened by 1/4 turn and the process continued until these were firmly in their seating slots.

The bearings and top race were then added to the bottom yoke, the new dust seal put in place before the steering stem was lightly lubricated with fork oil (because that is what I had out at the time) and the bearings and race heated up evenly with a blow torch for about 30 seconds and popped over the steering stem, and they slotted directly into place, no drifting required.

The process was repeated with the top race nut and both allowed to cool before continuing (time for a cuppa!).

Both of the bearings were then greased up with bearing grease and the lower yoke slide into the headstock and the top bearing nut applied to hold it in place. The top nut was tightened as tight as I felt appropriate (using a universal grab/super wrench to ease the job) to preload the bearings …



… before the top nut being slackened off and retightened by hand to just dial out any freeplay when rocking the bottom yoke.

The top yoke was then applied, by fitting above the top nut and using a mallet to drive the yoke onto the top bearing nut, and the fork stantions bolted into the yokes to align them ...



… before the stem bolt and locking nut were fitted and torqued up, the stantions removed and the job completed – looking good!

As always, if you'd like further details, please see https://motorcycleprojects.wordpress.com/
  • Fareham, Hampshire, UK
  • BMW K75RT Ultima
Wollyjumperuk
For more on my motorcycle projects - please see https://motorcycleprojects.wordpress.com

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