BMW R1100 RS
Kev Raymond returns with his Boxer twin.
BMW’S 1085cc oil-head twin continues to squat in my workshop, though the bike is now no more than a pile of sub-assemblies I am further dismantling for paint finishes, plating and repair as required.
As I have been stripping the bike it never ceases to amaze me that the bloody thing was still running and was even road legal when it arrived. Part of me thinks that it should have been ridden until it finally would not go and then be allowed to ‘rust in peace’, but the giant Scot/owner who has ridden it almost into the ground wants me to try and extend its life still further. She’s been reluctant to open up for me at times, though…
The first part to disassemble further was the top yoke, which had to have the ignition switch extricated. As with most bikes, the switch is attached with security bolts where the head snaps off when the required installation torque is met, making it difficult for thieving gits to remove. From my perspective, I have the unenviable task of drilling the blind heads off the bolts and then extract what’s left from the aluminium forging. I centre popped the heads, centre drilled them perfectly in their middles and then used an 8.0mm drill to remove the bolt heads. The front suspension and steering is somewhat curious as it uses BMW’S Telelever system. The top yoke is attached to the frame by a ball joint and as the yokes required powder coating, the ball joints had to be removed. Naturally, BMW asks that you use more of their wonderful (expensive and not readily available) special tools, but I wasn’t having any of it and as one of the special tools was simply a 46mm socket with a reduced diameter, I thought: ‘I already have a 6-point 46mm socket and a lathe!’ I measured the space where the tool had to go with digital calipers, put my ‘spare’ 46mm socket in the 3-jaw chuck of my lathe and used a good-quality indexable tipped tool to machine it down to fit the space. After reading the manual and seeing it is done up to 230 newton metres of torque, I didn’t muck about and fitted the socket to my Air Cat air impact wrench, which made it bump out.
I drilled the remains of the 8mm bolts that previously secured the ignition switch in place with a pilot drill, ensuring that the drill bit was parallel with the thread. I heated the yoke up to 120°C before attempting to remove them, aware that the threads would have had Loctite on them, before assembly. I used a professional thread extractor, which is somewhat different to the more prevalent ‘Easy Outs’. The cheap ‘Easy Outs’ usually cost around a tenner a set and are thin with a square end to be used with a tap wrench and invariably snap off, leaving one with a far greater problem than one started with. They’re too hard to drill out so spark erosion is the only answer. Such machines are expensive and owners need to recoup their investment. A decent set of professional thread extractors will cost slightly less than one ‘Easy Out’ being removed. You do the maths...
The side-stand pivot bolt was unwilling to be removed whilst attached to the bike, so I removed it complete with its mounting bracket. I clamped the stand in the bench vice, after leaving it to soak in ACF-50 for a few weeks. As it is removed by a relatively small hex driver it was not possible to attack it with huge amounts of torque, as it would undoubtedly round out; again it was time to break out my propane torch and make it very hot indeed to break the iron oxide bond, which has an increased area of contact thanks to the countersink head. Once it was mostly red hot, the errant pivot bolt finally succumbed to science and came out. Once out it became obvious that this fastener was scrap.
All the foot-rests and hangers, etc., had to be disassembled so that the various components could go to different places for refinishing. The steel fasteners, washers, springs, et-al would be going for zinc plating after a good clean-up. The aluminium parts that were previously powder coated would be chemically stripped, blasted and re-coated at Griff’s Reality Motorcycles. The foot-rests pivot on a 6mm pin that is held in place with an e-clip. As with circlips, it is not good practice to re-use them as they tend to lose some of their temper over years and after being stretched to be removed are unlikely to grip as they did in their youth.
I needed to remove the bearings in the swingarm and as usual used my blind bearing puller set, which in my book is an invaluable piece of kit for a motorcycle workshop. I tackled the left-hand first, but got less out than I had bargained for. The damned thing broke! The condition of the bearing face where the rollers contact was astonishingly bad. I selected a different collet part that would tighten up on what was left of the outer race of bearing. This time I used the heat gun to expand the aluminium holding the bearing, the vice-like grip doubtless aided by galvanic corrosion. This time it finally gave way and the remainder was successfully extracted. When it came to the shaft side, with the benefit of recent experience, I heated the aluminium up to about 120° before using the puller. Either the application of heat helped or the bearing was less corroded, because this time it came out in one piece.
I used my mate’s tyre fitting machine to remove the tyres because whilst I have manumatic tyre removing gear at home, I prefer to chew the fat about bikes and life and the universe with John and exert less effort. Manual tyre changing makes my back ache these days. The wheels were to be stripped and powder coated so everything had to be removed. The brake discs are far from factory fresh and whilst they have a little bit of life left, I suspect (hope) that the giant Scot will stick his hand deeply into his sporran for some new ones. A top tip for removing discs from any make of bike is to heat up the aluminium to around 120°C, which can be checked with an infrared thermometer, if you’re using a gas torch which could get stuff hotter than is ideal.
Almost all the factory disc bolts I have come across come with a dry thread lock that sticks like crap to a blanket and rarely come undone with mechanical force alone. Many Japanese bikes use cap screws sometimes with button heads and in my experience a combination of bi-metal (galvanic) corrosion and thread lock results in the hex rounding out before the thread lets go. I always fit a 3/8” drive hex (or torx as in this case) driver in the fastener after heating and give a good sharp blow with a copper-faced hammer. In this case as I was working with good-quality torx screws. I used my 3/8” drive battery-powered impact wrench, which delivers reasonable blows of torque, without tearing the head apart if it sticks fast, allowing me to concentrate on keeping the bit perpendicular with the fastener while the impact wrench does the work. When tugging on a breaker bar it’s only too easy for one to end up with the bit at an angle, which will encourage it to cam-out and wreck the head.
I used a seal puller to remove the oil seals protecting the wheel bearings. If I had a pint of beer for every time I have heard a tale of someone trying to remove a wheel bearing without taking out the retaining circlip (eh Bunny?) I would have a very cheerful month! I removed the circlip with my faithful old pair of circlips pliers, skipped the crustylooking clip before engaging the blind bearing puller set to extricate both bearings. Once the valves were transferred to the bin the wheel was ready for a swim in some very unpleasant chemicals to divest it of what was left of the powder coating.
Right, it’s beer o’clock, so I’ll see you all next month when hopefully we’ll be on the road to construction of shiny bits!