Third LS

 I had no intention of purchasing a third R65LS, but one came up in Tasmania that was of low km and which looked really sweet, so I considered purchasing it. 

My friends encouraged this. There is an agreement that when I have all three in roadworthy condition we will take them riding together. 

When I got the second LS I had really clear reasons to do so: redundancy (even if I sent the heads away for work I'd have a bike to ride) and diagnosis (keep swapping components until a problem was fixed). 

The new LS was just beautiful. Well cared for, low km, good price. So, after a few weeks negotiating its transport from Tasmania to mainland Australia it arrived home. 

I was aware that it had not been regularly ridden for years and that it would need a fair bit of work to get it properly roadworthy. There were more problems with it than I’d realised at the time of purchase, but nothing unexpected. The preliminary list is:

• Tyres. These are barely worn, but are dated 2012. When I do these I’ll replace the tubes and wheel bearings as well. 
• Steering Head Bearings. These were notched. Once I’d removed the forks turning the head stem was gritty. 
• Rebuild forks. Probably the oil in these is more than 30 years old. 
• Replace rear shocks. These were original, ikon replacements are on order. 
• Replace brake lines. These were stamped “09/82”. They weren’t leaking, but clearly overdue for replacement. I’ll also rebuild the callipers. The master cylinder had been replaced a year or so ago. 
• Fix crash damage. I purchased the bike knowing that the engine protection bars had both been bent back, but didn’t realise that there was a lot of fibreglass repair inside the fairing. There may be other problems associated with this, such as bent forks. 
• Fix oil leak from front engine cover. Probably the seal around the crankshaft (alternator rotor) has failed. However, if I’m going to pull all that apart I may as well do the camchain: the bike has done 55,000km, I would expect to do the camchain at 70,000km. The seals under the alternator and bean can will be replaced as part of this. 
• Rebuild the carburettors. At the same time replace the fuel hose and air filter. Oddly, the bike has been tuned without slack or free play in the throttle cables, it’s surprising that it was running so evenly. The bike is performing sluggishly, hopefully cleaning the carburettors will fix this. 
• Service the speedo. The odometer works intermittently, which casts some doubt on the 55,000 distance travelled. But, clearly, it’s not gone more than a couple of hundred km since the tyres were replaced in 2012. 
• Install LED indicator bulbs. 
• Normal service. Oils, filters etc. 

Jobs naturally divide into three groups – front end, camchain, carbs – which I’ll separate rather than do all the jobs concurrently. Forks first. 

First set of jobs, dismantle the front end down to removing the steering head bearings. 

Front tyre was manufactured in the 11th week of 2012 but has hardly been used. Handling on the ride home was poor, hopefully replacement of tyres, rear shocks and steering head bearings will fix that. 

Brake lines were manufactured September 1982 and are overdue for replacement. 

Brake calliper was filled with sludge. However, dust caps were in place and not degraded, and there is no rust on the pistons, so fixing this is a straightforward matter of clean and reassemble. 

The new bike has a VIN ending in “03”, the bike I purchased in 1996 ends in “17”. Other numbers, and the date of “09/83” are the same. So, they were 14 units apart on the production line, probably produced the same day. 

Progress to date has been straightforward - a few tight bolts, but nothing stripped, nothing broken. Broadly, lots of work needs to be done but not out of line for a bike of this age. 

Siebenrock 860 Kit

 For years I’ve resisted changes and upgrades to the R65LS, preferring instead to ride around its difficulties. If I wanted a larger or more modern bike I would at some stage have purchased one. 

In April 2024 I went on a long ride with friends on larger bikes and found that I was flogging the LS trying to keep up. Probably I did more than twice the number of gear changes that they did, even allowing for their 6 speed boxes. After this I decided that it was time to purchase the 860cc upgrade. 

I decided to have the heads reconditioned, forks rebuilt and rear shocks serviced as part of the job. These other items held the job up somewhat, and the bike was off the road for 3 months. 

I purchased the kit direct from Siebenrock. It was available from other places, but Siebenrock offered a R65LS-specific version of the kit that I didn’t find elsewhere. Part number was 1100870. Other R65 after 9/80 are 1100860. I don’t know what the difference is between the kits, and the other vendors I checked didn’t offer both. Everything necessary was in the kit: pistons, rings, gaskets, O rings, gudgeon pins. 

Installation was straightforward and could be done in a day if there were no glitches. 

After installation the bike had increased power throughout the rev range and was a joy to ride. It did lack a bit at the top end, which also changed the character of the engine. Always the LS has been moderate in the range from 3,000 to 5,000 rpm, pulled really well from there to 7,000, and then ran out of puff towards the redline of 7,500 rpm. Keeping the bike in the 5 – 7 thousand range has been key to spirited riding. With the 860 kit this emphasis on keeping the engine over 5,000 rpm has gone, it pulls cleanly from much lower down and this delivery is steady through the rev range.  

To fix the top end I went up 3 sizes in main jet, 138 -> 140 -> 142 -> 145. This was a guess based on the main jet sizes of different bikes in the Haynes manual: different LS were supplied with main jets 135, 138, 145 and 148, the 145 size was used on the 1982 US delivery bikes. With the increased main jet it keeps pulling strongly above 7,000 revs. The bike no longer runs out of puff towards redline. 

During the run in period I had oil temperatures of 140 degrees Celsius, as measured on the dipstick thermometer. This didn’t last long, but highlights the need to be gentle during the first few hundred km and to do an oil change afterwards. I believe the high temperature to be due to the piston, rings and cylinders scrubbing each other in. 

Curious three toned engine: new Siebenrock barrel; reconditioned heads; and grimy tappet cover.

A couple more notes. Some people use gasket goo of some sort to seal the cylinder base O rings and also the pushrod tube seals. I didn’t bother. 

Also, the Siebenrock kit instructions included that the gaps in the piston rings be offset at 120 degrees. A more precise method is suggested by Brook’s Airhead Garage where the gaps are rotated to avoid the thrust surfaces on the cylinders. I used 120 degree spacings as per the instructions, but would probably use the more precise spacings if I was doing it again. The precise installation is at https://www.youtube.com/watch?v=1I9RI3pVZHg  

I’d consider doing this upgrade on my other bikes, I’m really enjoying the extra power, and the cost isn’t too high. The main consideration is whether the bikes are kept stock or not. 

The valve clearances tightened up during the run in period: it’s important to use the “first 1000 km”  clearances of 0.15 and 0.25 rather than the usual 0.10 and 0.20mm. 

The R86LS stickers were supplied by Gian Sticherman, contacted via https://www.facebook.com/stickersmann.  The “Siebenrock 860” decals supplied with the kit were black and orange, so would stand out on neither the red fairing nor the black side covers. 

The bike vibrates less, the vibration characteristic of this model at 5,000 rpm is entirely absent. This is probably due to the Siebenrock pistons being better matched/balanced than the original. The pistons I took out were 378 and 382g (using kitchen scales), had they been more closely matched the bike would probably have vibrated less. 

R65LS Decal Mounting

The Airhead 247 podcast has extended itself into a video logs and also has a website. On the website they have a (incomplete) collection of technical advisories including the one for decal placement on the R65LS.

I hadn’t realised that the stickers were applied by the dealers. I’ve seen bikes with odd placement, including the rear sticker above the roundel rather than below, and also seen Henna Red bikes with the blue stickers appropriate for the Polaris Silver bikes. I’d thought that these were the result of mistaken alterations by various owners, but it seems that they might be mistaken application by the dealers.

The 247 website is at https://airhead247.com/. R65LS sticker placement is at https://airhead247.com/service-bulletin-r65ls-decal-mounting-00-026-82-2053-3-82/

The podcast concentrates on airheads but occasionally wanders into other areas like the BMW K series.

The R65LS engine, in common with R45 and R65, are type 248, not 247.  The two engine series have different strokes, 248 has 61.5mm compared to 70.6mm on the 247. (Other changes in capacity are effected by changing the bore.) I’m not aware of this being acknowledged on the podcast, they have used “247” as synonymous with “airhead”.

Haynes Manual

My primary reference for working on the bike is the 1986 Haynes manual. All six of the airhead BMWs that I've owned have been coverd by this manual. 

It is very practical, detailing what things happen to the bikes in service, how to troubleshoot faults, and suggesting workarounds for BMW special tools. Because it deals with such a long model range of bikes it has a detailed technical history, for example in describing the forks it describes at what model years forks were changed and which bikes received the new version. 

Current version extends the range, 1970 - 1996, and calls it "2-valve Twins" to distinguish it from oilheads. 

I have the BMW workshop manual as well. This is useful and I occasionally reference it, but in a practical sense I only use the Haynes version. The BMW manual is very proceduralised, focussed on disassembly, check/replace, and reassembly. It relies on a lot of special tools many of which could only be affordable to a dealer. 

Fork Gaiters

 The bike was originally released without fork gaiters, all the 1982 publicity shots have shiny stanchions. 

My first LS had fine 14 rib gaiters, quite slim and quite sharp on the concertinas. 

The realoem parts catalogue doesn't include gaiters. Some retailers have a bulky 11 rib version that looks like it comes from a R75/5 or similar. Motobins list this as "Code: 93900    BMW: 31 42 1 234 908".  This is more bulky than the 14 rib version, not as slim and the folds of the concertina are more rounded. 

With one of my fork rebuilds I found the 14 rib version in the parts catalogue for the R65 and R80G/S:

https://www.realoem.com/bmw/enUS/showparts?id=0348-USA-06_1980_2471_BMW_R_80_G_S&diagId=31_0318#31421241666

• 02 Ring 2 31421241669 $6.97
• 03 Rubber boot 2 31421241666 $16.90
• R 65 GS, R 80 G/S, R 80 ST (80-92) R 80 G/S Fork slider

The bulky version clamps directly onto the stanchion and slider. The 14 rib version clamps directly onto the slider but needs a neoprene ring at the top to make up the difference between the stanchion and gaiter. 

I prefer fork gaiters, I like the idea of protecting the stanchion from dust and stones. I think the 14 rib version looks much better on the bike than the thicker one, but maybe I'm just biased because of my history? :-)

11 Rib version on the left, 14 on the right. 

Wedgetail Ignition

 About two years ago I became concerned about the bean can on my 200k bike and rebuilt it. This was successful, but I was never really confident that I'd done it as good as new, so I purchased a Wedgetail ignition system. This includes both the sender unit (slightly flatter than the bean can) and ignition control unit to sit under the tank and control the coil. I use a 1.5 ohm Dynacoil, not the OEM version. 

The parts arrived well wrapped but the ICU was damaged, presumably drop kicked during transit. It was replaced without delay or argument. 

It's worked faultlessly since installation. 

ICU Under Tank

The systems are built in Australia, available in the USA, and have a Facebook page. 

Starter Motor

 On a ride recently my bike started unreliably: there was a "click" from under the tank but no life from the starter motor. In each case I was able to get the bike started after a few attempts and moving it around a bit. I wasn't sure if the problem was the relay or motor itself, but neither has been serviced, ever, so I figured I'd replace both.

I purchased an Arrowhead starter for AUD219. This was less than twice the cost of overhaul parts for the original BOSCH starter. 

Shiny new Arrowhead starter installed.

Replacement was straightforward except for a couple of points. 

• There are two hex head bolts holding the starter in place. The one on the left side of the bike could be turned using a ring spanner, but the housing wouldn't allow this on the right. I had a socket that fitted, but to get access for this I needed to remove the airbox and battery, which was a nuisance. When reassembling it I used an allen key bolt, so this should be avoided next time. 
• There is a bracket on the leading edge of the starter under the timing chain cover. It has 3 bolts, two on the starter and one on the engine. One of the bolts on the starter is impossible to get off while the starter is in place, but the lower bolt, screwing the bracket to the engine, can be accessed using a 10mm socket from the front. 
• The relay I purchased had 4 connections and is appropriate for other functions on airheads, but not necessary on my bike. The correct relay has 5 connections. 
• Care needs to be taken removing the relay with a screwdriver because one of the connections is always live, and so can spark. 
• The crankcase breather hose was perished, clearly visible in the pic, and was replaced. 

LHS Spanner Access

After this was done with the original starter relay in place the bike didn't start, so I swapped in the relay from the other bike and it started sweetly, no problems. So, the problem from the beginning was the relay, not the starter itself. 

Shiny new Arrowhead starter installed.

Second Bike

 In September 2019 I purchased a second R65LS, broadly identical to the first: both red, both with Brembo brakes, both with stainless exhausts, but 1984 rather than 1983 and only 135,000km on the clock. It looked like a good deal, purchased from the mechanic who had maintained it for the last 20 years. It arrived on the back of a truck looking as good as it had in the pictures. 1983 on left, 1984 on right. 

When I went to get it registered the problems started, and they have only recently been properly ironed out. 

First problem was that it wouldn't rev above 4,000 rpm. There were lots of little problems with the carbs, each time I'd reassemble them and hope that the latest minor fix had resolved the problem, but eventually I did a full rebuild. It turned out that the seller's idea of "recently rebuilt carburettors" didn't involve replacing all the O rings or cleaning the main jet holder. Weirdly they had assembled one of the diaphragms rotated: it's surprising that the bike could be tuned at all. 

The image shows that the piston is rotated (the diaphragm is located correctly in the carb body, the problem is that it has been fitted to the piston rotated). 

Riding on the freeway a vibration was setup that suggested a failing wheel bearing, but when I pulled off the road the rear brake came on and locked in place. I'd noticed that the gearshift was in unusually good condition for such an old bike, it had been replaced and somehow part of the original had fallen into the housing of the rear brake pedal, jamming it on. 

Always find the bit you drop!

The engine note changed and then the exhaust flange nut on the LHS cylinder came loose: it had been held on only by one thread and a stack of grease. This was sleeved and rethreaded by an engineer. 

The pin put through the sleeve to the cylinder head is just visible. 

The carburettors were now running but difficult to balance. I had some holes in the header pipes welded over to fix this. 

Keeping two identical bikes is a bit odd, but there are lots of advantages. Obviously I can ride one while the other is off the road for maintenance. And I can swap components to troubleshoot. I have little experience maintaining bikes apart from airhead BMWs, and all my skills are easily transferred between the two LSs. 

I'm now to the point I expected to be a month after the purchase: two bikes, either of which I'd trust to go riding. 

Variations

BMW manufactured the R65LS from 1981 to 1985 in two colours, henna red and polaris silver, and two delivery markets, EUR and USA. Some modifications were made for different delivery countries, these are listed as "national version" on RealOEM.  There were a plethora of variations on these two themes some of which suggest that the bikes were completed from a spare parts bin.

Carburettor. The Haynes manual lists minor variations in the carburettor jetting between UK and US models and between 1982 and subsequent production years. Particularly, there are 4 main jet sizes in these combinations. 

Dashboard. Some bikes have "TURN" stamped in the centre of the green dashboard indicator lamps.

Decals. Usually the red bikes had a black and white decal and the silver bikes a blue decal. However, some red bikes had blue decals and some silver got the white. The decals were shipped alongside the bike and the dealers attached them prior to sale, so they may have changed decals based on preference. 

Engine Number. The 1983 bikes had the first 7 digits of the VIN stamped above the oil dipstick. They also had an engine number stamped on the lower left of the engine, just above the sump, like "12345678 652VB". Later bikes had just the latter. All my bikes have "652VB". According to the local authorities the correct engine number looks like "83409853 652VB" but some rego papers use the 7 digits from the VIN. 

First Aid Kit The first aid kit was optional, but where fitted there was a red sticker on the LHS side cover indicating that it was under the seat. Similarly some bikes came with a tyre pump and a security chain that fitted into the frame tube. 

Fork Gaiters. The 1982 bikes had no gaiters. Subsequent bikes had a 14 rib gaiter. The current spare parts pairs a bulky 11 rib gaiter to this model, but the original is still listed for the R65GS and similar bikes. 

Front brake callipers. Most bikes had Brembo callipers, but some had ATE. Both had 36mm pistons. Some Brembo callipers had 12mm mounting holes and a "top hat" spacer to shim them to the M10 bolt, others had 10mm holes. 

Front brake master cylinder.  The shop manual lists both 15mm and 16mm diameter. Both my bikes have 15mm. 

Fuel Tap. Most bikes have the delivery horizontal, but some bikes have the delivery straight down. I think that the latter fuel tap type is suited to tanks with a tap on both sides.

Gear Shift. Some bikes had a rubber gaiter on the arm from the gear lever to the gearbox. 

Ignition. US delivery bikes had the headlight always on, so the ignition had only 3 places not 5 as on other models. They also had a headlight relay setup so that the headlight would extinguish when the starter was being used, other bikes having no headlight relay.

Kick Starter. Some bikes had a kick starter. It seems that this was offered as an option on new bikes. 

Handlebars. RealOEM lists the usual small bars and a higher variant, I've not known the high version to have been used on any new bike. 

Hazard lights. Some bikes had a hazard light switch in the centre of the dash.

Reflectors. Some delivery markets had extra reflectors. Particularly, the USA delivery bikes had round red reflectors on the sides of the rear mudguard. 

Seat Strap. This is listed as part of the national version for Japan and France on RealOEM, I've never seen one: RealOEM

Secondary Air System. Some US delivery bikes had hardware that reduced pollution by providing fresh air to the exhaust manifold. This system included a pipe from the airbox to the cylinder head, hoses from the vacuum port at the front of the carburettor to the airbox, and some valves inside the airbox.

Sidecovers. Most bikes have black side covers, but some are painted to match the tank colour. Some of the original silver bikes had silver side covers, but most have unpainted black. 

Speedo. (Obviously) Kilometres for Europe and Australia, miles for UK and US.  Japanese delivery bikes had a flashing light that illuminated over the national speed limit of 80km/h. 

Tappet Covers. Mostly unpainted (silver) but some bikes have black.

Wheels. These were painted white on red 1982 bikes and silver afterwards. All silver bikes had silver wheels. 

Do you know of any other variations?

Brake Lines

In March 2019 I replaced the original brake lines with Venhill braided lines from Motobins.

The original rubber lines were overdue for replacement. There were some irregularities (bumps) on the outside of the lines, and one of them released a bit of fluid when it was flexed.

Brake fluid on top one after flexing. Not also slight bulge in rubber casing. 

New, shiny lines. 

Needless to say the braking ability of the bike was substantially improved after this. 

Works BMW Flat Twin

The book Classic Motorcycle Engines has a chapter on the 1955 works BMW flat twin. I've uploaded it to:

https://drive.google.com/open?id=1gLaaD_xzHFQNXzSrnkPifBdrWnM_IWkg

The book was published 1986 and had detailed technical descriptions with historical context on 20 outstanding engines. In the case of the BMW chapter the engine under discussion dates from 1954, so the drawing and original discussion 1955, and the historical discussion dates 1980s. 

The technical description of the engines is incredibly dense, packing an almost unbelievable amount of information into each paragraph. I dipped into it tonight and I'm sure there was information that wasn't there yesterday. However, if you don't read it attentively you might miss things like the reference to the 500cc flat twin with desmodromic valve gear, unfortunately abandoned because of lack of funds. 

Full citation is "Classic Motor Cycle Engines: a new perspective on 20 outstanding designs", Vic Willoughby, 1986, Motor Racing Publications Ltd, Great Britain. 

Enjoy!

Carburettor Rebuild

After what I imagine is 35 years without disassembly I took the carburettors off the bike and rebuilt them. I replaced:

• All the O-rings. 
• The diaphragms. Both were inflexible. 
• Cap screws. These had corroded somewhat. 
• Vacuum Blanking screws. These were damaged from repeated removal. 
• Throttle shafts and screws. The peening of the original screws meant that they damaged the brass threads on removal. 
• Gaskets on cold start and float chamber. 
• Main jet washer. These were a bit corroded. 
• Throttle and cold start return springs. 

A few pics of this:

Before: 35 years of gunk. Note the carburettor on the left has the cold start spring replaced with a pair of other springs.

Before: The carurettor on the left, with the darkened piston, is the one with the damaged diaphragm.

Diaphragms. The one on the right is so badly damaged I'm surprised I was able to tune the bike at all. 

After: all clean, ready for reattachment. 

A few comments: 

• One of the main jet holders was difficult to remove, there was so much gunk in it that it wore the threads down as I removed it. It reassembled okay, despite this. 
• I couldn't adjust the idle down on the LHS carburettor far enough to be able to set the idle mixture. I removed it from the bike and reseated the throttle butterfly, being more careful this time to ensure a good seal against the throat. 
• I had no device to remove the peening on the throttle butterfly retaining screws, and damaged the threads on the shaft when I removed them. I replaced the shafts and screws and used lock thread on reassembly. 
• I crimped the fuel hose attached to the LHS carb on reassembly and it got no fuel. Replacing that section of hose fixed the problem. 
• I don't have a compressor so I used a can of compressed air and a can of carburettor cleaner. 
• I found this youtube clip from "Boxer2Valve" immensely useful: ·         https://www.youtube.com/watch?v=MpBA6wimjLc&list=PLXo0yJ7WoKfvSNxo1uZU3qupxkkf9xU4w&index=5 

•  Probably I should've done this 20 years ago. 

The bike is running much better, it pulls better and I think that the range has increased 20%. 

Hand Guards

It's winter in Oz so I've gone looking for a way to stop my fingers from freezing. These handguards are black versions of ones fitted to R80GS models. I sourced them from Munich Motorcycles.

Part number is 71609062160. The white equivalent is BMW: 71 60 2 303 496. I'm not aware of any bike for which these guards are standard equipment. 

Installing the guards was straightforward but fiddly: I needed to loosen the handlebar retaining bolts and cut a couple of cable ties before I could wiggle the RHS one into place. 

They help considerably on cold mornings.  :-)

Nearly-There Sportster

In the dusty archives is this road test of the LS from 1983. The scan is from the yellowed pages of "Two Wheels Road Tests: Full tests of the year's top bikes" and includes other bikes like the Kawasaki Z750GT and Honda CBX550.

The LS was new at the time and wasn’t necessarily seen as an improvement on the recent BMW models or the R75/5 from 10 years previously. It wasn’t seen as a cost effective way to purchase a motorcycle: it carried the premium associated with BMW but didn’t have the robustness of its pedigree nor the performance of its peers.

It’s been a while since I’ve seen a Z750GT or CBX550 on the road, though…

Access it here (file is 20MB). 

My Bikes

I rode a Honda CB400T in 1985, and at the end of the year swapped it for a 1983 BMW R65LS. This I rode for more than 2 years before swapping it for a Ducati SD900 Darmah. After this I had various BMWs: a R80G/S, a 1985 R65 Mono, and a R100TIC (the police special R100RT). After selling this I went without a bike for a year or so, and when in 1996 the itch again rose I found another LS, identical to the one that I had sold in 1988.

In 2019 I found a 1984 LS in good condition at reasonable price and purchased it. It took 6 months to sort out the teething issues, particularly with the carburetion, but it now provides the advantages of identical historic bikes: I can ride one while I work on the other; I can troubleshoot problems by transferring components; the restriction to 60 ride days per year is now two rides per week; and their performance can be routinely compared.

The two bikes are in everyday use. The 1983 model has just over 185,000 km on the clock and the 1984 model 140,000.