In retrospect it’s probably quite easy to analyse a given course of action. In reality, however, it more than likely would turn out to be nothing more than pure impulse. We are all creatures of habit, and I'm certainly no exception. So what made me, having only previously owned Oriental two wheelers, buy a BMW Boxer? Probably impulse, or fancying change, or old age or a combination of all three. Who knows for sure? One thing, though, after about 900 bills changed hands I was the wondering owner of a 1974 green and smoke grey R90S.
I did quite a lot of wondering over the following few weeks. Wondering if I'd done the right thing, wondering if they all shook like this, wondering if the clutch and gearbox ever did work together in a reasonable fashion. In short, this was like no other motorcycle I had ever owned, either to look at, work on or to ride.
If you are not familiar with BMW’s boxer range, and you’re thinking of buying one, do take along someone who is clued in, because everything is as different from a Japanese machine as you can possibly get. To someone used to a well maintained rice burner, it sounds like the top end is shot, camchain knackered and the engine shakes about in the frame like the crankshaft is about to break free. Believe me, take a BM freak who knows the difference between healthy and unhealthy rattles - if there're no rattles at all then something's wrong!
One of the first things I noticed about BMW ownership is the speed at which your skin thickens. This is an inbuilt act of self preservation to protect you from the obligatory and relentless slagging off you will undoubtedly receive from mates and enemies alike. If you do not make yourself immune to this brigade you will definitely end up with a persecution complex, and they will love it when you cry. Possibly the worst thing is the fact that you can't really explain why you bought a tractor/JCB/cement mixer, because it was impulse. Remember?
In a lot of ways the R90S was a tradition breaker. It had some very different characteristics that made it stand out from other boxer twins. Generally, these twins had a fairly relaxed manner of power delivery, and were best ridden thus. Not so the R90S. The bike had pretty tall gearing and gives its best toward the top end of the rev range, 5000 upwards. This bike is not happiest around town and will make sure you get the message The dry clutch also gets overheated and what is always a snatchy action becomes a virtual on-off switch.
It’s not uncommon to use no more than three gears in town. The riding position tends towards sport rather than tour, so your wrists and forearms take a pounding below 60mph. Once clear of the town, however, the bike comes into its own. On a good open road sitting at 60mph plus the gearbox is redundant and cruising like this is when it's at its best. At around 6k in top gear, 100mph, all vibration ceases to exist and the temptation is always there to sit at the ton whenever possible. The handlebar fairing gives moderate deflection of the elements up to the legal limit, after which you will be required to do your jockey impression.
Stability, straight line or otherwise, can be very good on these bikes, but it depends on how well it has been set up or maintained. Firstly, stick with Metzs - they give predictable results. Sometimes it doesn't really pay to experiment, unless you're into skin grafts. Check the wheel bearings for excessive play. If there is more than the permitted amount, don't worry they are adjustable, so unless the bearing has been run dry it should still be serviceable. One thing worth remembering, high pressure water hoses can get water past the wheel bearing seals.
The bike is very sensitive to steering head bearing wear or maladjustment. Overtightening is one of the most common causes of poor handling, and will also knacker the hearings in short order. Fitting new races at about 40k was a pig of a job. l'm not aware if there is a special tool available for this task, but I ended up with no bike for three days while I made up various bodged pullers and applied them to the job.
On the other hand, swinging arm bearings are a lazy man's delight. Just pop off the dust covers either side, stick a little adaptor on your grease gun and pump away until clean grease comes through the other side. These bearings are also adjustable. Keep an eye on the tightness of the large locknuts either side of the swinging arm. I had the questionable honour of riding mine with only one side of the arm attached after the other worked loose. A somewhat similar effect can be obtained by riding with about 5lb of pressure in the back tyre. However, with good tyres, fork seals and heavier oil, and with all the relevant bearings in top order, stability and handling are good, for a seventies period piece.
The brakes are a bit of a throwback. They work fairly well in dry weather but either lag or don’t work at all in the wet. They are completely useless in rain in heavy traffic. If the engine didn't possess such good braking power you'd be well advised to stay at home on wet days. The later Brembo calipers are reputed to be a great improvement, but the R90S only had ATEs as standard.
General routine maintenance is a doddle. Valve clearances are a ten minute job but the points can be a bit fiddly due to the positioning of the mechanical advance/retard unit, for which there are stiffer springs available, curing its tendency to advance too quickly. Keep a careful eye on the engine oil level as all R905's use it in varying degrees. Mine needed half a pint every 500 miles or so.
The battery gets a hard time on all Beemers, and is usually cream crackered after a couple of years maximum. Despite what you've probably heard they are not particularly hard to fit. The electrical system is unfailingly reliable, in most cases, though, the site of the relays under the petrol tank is well placed to catch all the road crud. Having said that, the only one I replaced was the starter relay. A 100/80 watt light bulb was the only other alteration I had cause to make.
This, and other early model BMWs have rubber pushrod seals which have a tendency to weep slightly. Replacement is cheap and easy. Don’t waste time with original or pattern type exhausts, do yourself a favour and buy a Keihan stainless steel system, then forget about it for the duration of the next 10 guaranteed years. For parts and accessories l used the Ultimate Source and James Sherlock, with no hesitation in recommending both.
When I sold the bike in early ’91 it was 17 years old. From what l've seen of more recent BMW models they do not have anywhere near the same quality of build. The R90S still had the original paint on the frame and it still looked pretty good. Dream Machine resprayed the cockpit fairing as original due to stone chip damage, the remaining paint still polished up well.
The engine had 50k and was still sound. I did very little beyond servicing and replacing consumables, and yet after six years I sold it for nearly three times what I paid. Not many motorcycles I can think of will put a smile on your face and make you a profit when it's time to change. I did feel like a traitor, though, and if it had been viable financially I would loved to have kept the bike, but it wasn't, so I didn’t.
If, perchance, you are considering buying a BMW R90S remember this is no ordinary BMW, and if a R80RT is what you like don't buy an R90 instead or you will be sorry. It would be more truthful to compare it with crafty old dogs such as Laverda Jota, Guzzi Le Mans and Ducati 900SS.
As I discovered, they hold their price remarkably well, so bargains are rare but not impossible. Different they are. I rode mine in Northern Ireland for six years and never once saw another on the road. Mind you, there are a few tucked away in garages here and there. Money aside, it's a really desirable bike with loads of that elusive character, fun to ride and - due to a short production run - moderately exclusive. It's very solid reliability and outstanding build quality have withstood the test of time; I don't sneer at BMWs any more.
Davy Vance