FAQ

BMW R series 2 valves per cylinder, known also as Airheads, were produced in their hundreds of thousands since 1968 until 1996 and are quite famous for their build quality, reliability, good handling and engineering excellence. Because there are so many survivors, these bikes tend to be underrated and under priced, but with a loyal legion of cognoscenti giving it its true value.

Parts are plentiful, used or new, at very decent prices.

So, no wonder that a lot of these bikes, with quite a few over 30 years old, are still used everyday, even for commuting!

Any /6 Series bike onwards (1973 on) will be a good starting point as /5 Series (which have Short Wheel Base chassis) are quite sought after, with prices inflating all the time. The lowly R45 that appeared in 1978 along with the R65 is quite gutless, the R65 is sweet to ride and quite light, derived from a similar chassis but made of thinner gauge steel, and fairly fast at close to 110mph, so quite a good option as they are already equipped with nice features such as Brembo brakes. The iconic R90S is quite valuable and a pity to transform in a Cafe Racer, R90/6 is quite fast but rare in UK, the /7 Series R75 or R80 are very sweet and better balanced than the 1000cc engines, especially perky after 1981 with lighter flywheels. R100's have more torque but vibrate more, nevertheless are quite fast with potential for 124mph+.

I would recommend a BMW R80/100RT or RS as a good starting point as they are quite easy to find and you can sell easily the plentiful surplus parts (panniers, fairings, seat, tank etc) to offset the conversion costs, keeping the budget at an acceptable level.

Of these bikes, the /7 Series still have the heavy flywheel to smooth power delivery, which is advantageous for touring but hinders acceleration figures. Ignition is by contact breakers, which although reliable, do require some maintenance and never quite as nice as a proper electronic ignition. Several aftermarket ignition kits are available such as the Boyer Brandsen or Dyna or owners can simply retro-fit the electronic ignition kit from the later (post 1981) bikes. Brakes can be marginal in their performance with the dated sliding ATE brake callipers and the remote, Bowden cable operated brake master cylinder, sited under the tank. Beware of cracked or bent “Snowflake” cast alloy wheels, which were recalled in period due to their notorious softness but there could be machines that escaped this recall.

Post 1981 bikes saw an improvement by having more powerful Brembo brakes, lighter flywheels and electronic ignition.

The Post 1984 bikes are known as the Monolevers, due to their single sided swing arm design and later turned into Paralevers (very refined swing arm and driveshaft arrangement), with more modern forks and Brembo 4 pot brake callipers. After 1987, the engine and its heads were modified to run on Unleaded Fuel. These are quite excellent bikes but with more modern looks that may not suit an old style Cafe Racer but are an excellent proposition for those requiring a more modern feel to their bikes.

We would recommend that you familiarize yourself with these models, being by reading several publications or articles on the net, posted by forums, clubs etc. I would recommend the purchase of the Clymer manual or the rarer (and costlier) BMW original workshop manual, for simpler maintenance tasks, the Haynes manual is also recommended.

Although these engines seem to go on forever, other ancillaries are not so long lived, especially after several decades of possible neglect, DIY home mechanic ham fisted approach and serious bodging, so look carefully for evidence of good care as in any other bike.

Main points to look are:

• Battery charging OK? Alternator failed windings or faulty regulator can play havoc.

• Brakes seized? It is fairly expensive to rebuild brake callipers.

• Transmission smooth? Final drives splines and wheel bearings can wear and it is expensive to rectify problems, check for excessive play and clunks.

• Leaking gearbox or box-driveshaft gaskets or rubber gaiter? Not expensive to fix at home but very time consuming for the uninitiated.

• Noisy valves? Can be normal but no noise at all can spell problems with valve recession due to unleaded fuel on pre 1987 engines. Smoke from the left hand cylinder on the start up is normal (oil drips through the valve guide onto the combustion chamber) but beware of valve guides wear, so if a lot of smoke on the over-run and after idling for a while, time to replace, noisy cam chain is also common and cheap to replace but time consuming, although these engines seem to run forever!

• Post 1981 bikes have Nikasil coated cylinders (directly on alloy), which cannot be bored and re-used as a normal steel sleeves, they need to have a new Nikasil treatment afterwards so beware of inter-galactic mileage where oversize pistons or rings are needed, as it is more expensive to rebuild than a normal engine.

• Heads been converted to lead-free fuel? Not really important, but nice to have it done but beware that some less professional companies have carried out this change on the valve seats, only for the seats to fall out and destroy the engine, You can always use an additive such as Castrol's or Miller's on the fuel if you mileage is not that high.

• Rusty exhaust system? Beware as headers are expensive to replace (stainless-£180).

• Lazy starter? Could be battery discharged or plain old. Starters are very demanding on amperage.

• Wiring loom bodged? Ex-police bikes are notorious for this, best budget for and fit a new one.

• Gearbox smooth? Although long lived, everything is finite, look for false neutrals and jumping out of gear, rebuilding is looming.

• All switch gear working? Can be expensive and time consuming to replace.

• Clocks working? Case very often is cracked around the mounting or speedometer needles brake or neutral light doesn't show due to gearbox switch being U/S, pain to replace.

• Pitted or leaking forks? Beware, if gaiters have cracks, dust will settle in, damaging seals and eventually the hard chrome, look for pitting around yokes and fairing gaiters.

• Soggy and wobbly handling? Tired forks, which can be renewed with some Progressive Suspension springs (£60) and new seals and fluid. To eliminate the vagueness from the handling, a Fork Brace (£100) is recommended, it will give a sharper feeling to the handling.

• Rear shocks? Original Boge units? If rusty or original, their performance may be down from some many years riding, usually with pillion and hard luggage. Hagons' are £115 and Ikon's £260.

• Tyres OK? Are they matched? Check for cracks, wear and age (marked by 4 numbers, indicating week and year of manufacture).

• Rusty bolts everywhere? These are signs of neglect and can also be a pain to remove, haggle accordingly.

• Rusty, cracked, dented cosmetics, missing luggage? Not an issue in a Cafe Racer project, but an haggling point as those parts could be sold to offset the cost of the Cafe Racer conversion.

There are truly good bikes out there, that have been maintained by enthusiasts so it shouldn't be hard to find one that is in a good, honest condition. Look for ads in the BMW Club. Ebay and similar auction/sale sites might yield few bikes, but in my experience, a lot of dogs (or lemons) get flogged there for the unwary and gullible. Treat these auctions as a normal buying procedure so always inspect the bike personally, don’t rely in grainy pictures or half-promises.

Always ask the right questions about history, maintenance and servicing, don’t be afraid to walk away in case of doubt. As with any other vehicle, always buy the best you can afford. No point in buying a heap for £800 and then spend £2500 rebuilding several components when you can buy something really nice for £1500-1750.

Tanks have proved to be very resilient to fuel as we provide a special coat on the inside (based in vinyl ester and isophthalic materials) to further enhance its leak proof capabilities but please note that if you use some of the Alcohol based fuels in higher concentration, we have no chance to assure you that ethanol fuels (like the common E85) will not affect the tank on the long term. In fact, the best material for ethanol storage would be stainless (preferably 304 or 316) as ethanol absorbs vast quantities of water and can corrode certain types of metal, plastic and rubbers, with disastrous consequences to our engines

We can assure you that normal fossil fuel (gasoline) will not affect the tank, in fact, we’ve got a fibreglass tank from end of Fifties made in Germany for a R50 BMW in an amazing condition!

Please note that Ethanol fuels can also damage your bike through water accumulated which can create backfires in your engine and bad running, destroy the rubbers and plastic components in your steel tank, fuel lines and carburettors internals and promote corrosion within your combustion chambers if the bike is laid for too long. This is the reason why modern vehicles designed to run on E85 come equipped with different construction materials and water filters from factory, to resist corrosion in rubbers, plastic, steel, etc.

Some countries do not permit the use of a GRP fuel tank for normal road use (in UK it is allowed), its use being restricted to private and off road and racing events. The theory being that in an event of a crash, the fuel tank could crack and spill its fuel, causing fire although a metal tank would probably split easier along its seams in the event of a violent crash. Obviously, the best material to safeguard this would be a fuel cell employed by racing teams, using Kevlar and other man made fibres but its cost is prohibitive and not suitable for cosmetic applications such as a bike tank.

It is your responsibility to ensure you obey your country legislation so please ensure that you are not breaking the law by consulting your relevant Government officials.

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