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. 

Shorting Adaptor

The carburettors can be balanced by either using vacuum gauges or by alternately disabling one of the cylinders and tuning/adjusting the other. I did this for years by swapping the standard spark plug leads for car leads with exposed contacts. I could then disable a cylinder using a screwdriver to short the exposed metal around the plug to the cooling fins.

There are various shorting adaptors available on the internet for purchase, but I found that I could make one using a metal drawer handle. The standard threaded screw used for attaching these is roughly the same diameter and pitch as the thread at the top of spark plugs.

This is the drawer handle with a plug screwed in instead of the normal mounting screw.

With the posts unscrewed from the handle. The screw through the middle has had its head cut off.

Installed on the bike. The exposed metal allows shorting to the cooling fins.

16 January 2024: An update on this: I realised eventually that the thread is the standard M4, so some long nuts and bolts and couplers are all that is necessary:

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%.