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”.

BMW Desmodromic Superbike

 

In the January 24 2007 edition of Australian Motorcycle News I found a curious article about a desmodromic BMW. It was under development but never raced in the superbike class for which it was intended.

The design references the “legendary Rennsport 500cc Boxer GP Engine” described in Classic Motorcycle Engines. It has a number of important differences:

• Cylinders are rotated so that the air intake is a downdraft from the top and exhaust is directly out the bottom.
• Camshafts are driven by chain rather than bevel shaft, with a secondary chain driving the inlet cam from the exhaust cam.
• The exhaust cam on the bottom of the head has been staggered slightly to give better cornering clearance. This makes the head look a bit like it has been tilted or bent in at the bottom.
• Bike is 1000cc. 

The bike was developed in the early 1990s and, apart from an outing at the Goodwood Festival of Speed in 1999, has been hidden or a museum piece.

I've uploaded a scan to https://drive.google.com/file/d/1Z_2zaSxT7sOq7AZTG9WCpb1LXAz4HwYF/view?usp=drive_link

Original was Australian Motor Cycle News, Vol 56, No 14, 24 Jan - 6 Feb 2007. Author Alan Cathcart, Photography Arnold Debus. 

Drivemag have a similar article, also by Alan Cathcart: https://riders.drivemag.com/features/bmw-boxer-r1-desmo-test-stillborn-superbike/

Desmodromology have a page on it and mention that 4 were built but only one is rideable: https://www.desmodromology.nl/bmw-r1/