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See the steps below to check the correct operation of a condenser.

The table below shows the radial clearance specifications for all bearings used on the R24 – R69S models

It’s a wide spread misconception that pistons must be round / cylindrical. The opposite is true, This is a new Kolbenschmidt R27 piston 68.50 mm:               From the Internet: Profile: If you roll a piston across a flat surface, you’ll notice it doesn’t roll in a straight line. This characteristic is called profile. Aluminum conducts heat significantly, so pistons are designed with a taper. The top of the piston (near the crown) has a smaller diameter than the bottom (near the skirt). The skirt itself is shaped like a barrel. This taper allows the
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The only difference between the Denfeld en Pagusa saddle is the saddle deck. There are small differences between the saddle deck frames: the shape of the frame and the front threaded bolt. The Pagusa saddle bolt it is a bit longer and has a spacer so that the front of the saddle deck sits +- 1.5 cm higher compared to the Denfeld saddle deck. The grain texture of the Denfeld rubber saddle deck surface is finer than the Pagusa grain texture. There is no quality difference All other parts are the same: subframe, Z-bracket, rubber spring, spring stop piece, mounting
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  Click thumbnail to open the list. R24 – R27           R51/3 – R68           R50 – R69S            

Comparison of the different gearbox cam plates used in the R24 – R27 and R50 – R69S models. For more information about the R50 – R69S shifting system, click following links: Smooth shifting R50 – R69S R50 – R69S Old and New style shifter mechanism  

This is specifically aimed at 1 cylinder and /2 gearboxes. If you’ve tried everything and you can’t figure why the gearbox shafts do not turn freely, you can use following very time consuming method  🙂 to determine the cause: Instead of putting all 3 shafts in at the same time, put in 1 shaft at the time. Remove the input shaft seal from the gearbox: the seal makes it harder to rotate the input shaft, making it difficult to assess whether the shaft is running freely. Remove the idler gear and kickstarter gear segment. Whenever you install (and remove) one
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Some rubber parts are still provided with a (wax) layer when shipped: a mold release agent. A cleaning solution with hot dish soap and water is enough to remove this layer. Use rubbing alcohol for stubborn stickiness. Although alcohol is an effective cleaner for most kinds of stickiness, you should only use this cleaning agent on rubber occasionally. Dampen a clean rag with alcohol and wipe at sticky areas until they are removed. Rinse the rubber with water afterwards. Exposing rubber too often or too long to alcohol may cause it to break down more quickly than normal.

A “strenght & weakness” overview of the different seal materials available in the market.

Very informative video! https://fb.watch/gQycYmmz_h/    

The oil slinger screws are not available from BMW anymore. Most suppliers now offer a general purpose DIN 963 M6 x 10 screw. However, the head of this screw is higher than that of the original screw: the head of the screw protrudes above the oil slinger surface. This may be undesirable in some cases. We now supply oil slinger screws with the same dimensions as the original screw.

The BMW specification for the radial clearance of the conrod big end & crankpin is based on the use of slightly spherical rollers in some of the crankshafts. The use of spherical rollers prevents the rollers from “biting” when the crankshaft flexes at high RPM. Today the new FAG Dürkopp conrod sets are equipped with cylindrical rollers. This requires a slightly larger radial clearance to prevent the rollers from getting stuck when the crankshaft flexes at high RPM. Spherical rollers (used) are identified by the wear track in the center of the roller:                
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These photos show the difference between the Noris keys and the replica keys. This can help to identify the cause of malfunctioning ignition switch.      

If the valve adjusting screws have reached their end and there is still insufficient valve clearance, the cause may be (a combination of): the valves sit too deep in the valve seats the cylinder head sleeves have sunk deeper into the cylinder head over time. In our experience, the sleeves at the exhaust side sit usually deeper than at the intake side. Below an example of 2 R27 cylinder heads. The RHS sleeve at the intake side of cylinder head 1 has a height of 88.47 mm The LHS sleeve at the exhaust side of cylinder head 2 has a
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Click image for table    

This video shows the repair of the idle mix thread: a thin alu-bronze bush of M8 / M7 x 0.75 is installed in the carburettor, realizing a very wear-resistant and strong thread Click this image to watch the video on Youtube:  

Staburag is a good alternative for “Prussian Blue” when determining the contact pattern between the crown and pinion gears. By adding a few lines, the contact pattern becomes even easier to read.                  

The drive shaft flange has a press fit with the shaft. A workshop press is needed to press the flange off and onto the shaft. When removing the flange, standard press plates can be used to support the flange. However, to press the flange back on, the drive shaft collar must be supported. There are several ways to do this, but this tool works best for us. The tapered shape of the 2 halves and the ring ensures that the shaft is increasingly clamped during pressing. The edge of the hole between the 2 halves follows the radius of the
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Recommended press fitting for valve seat inserts in aluminum cylinder heads: OD insert 30 – 40 mm: 0.15 mm / 0.0059″ OD insert 40 – 50 mm: 0.18 mm / 0.0071″   Spindle speed for cutting a seat pocket in aluminum cylinder heads: 400 – 600 rpm It’s recommended NOT to freeze (f.i. with liquid nitrogen) the sintered valve seat inserts before installation. The valve seats are to be pressed in with a flat and square seat driver tool. The valve seat is inserted with the radius side down.   Source: DuraBond

Some statistics based on last 5 years (2013 – 2018)      

All Matra tools with spindles such as M355, M499 / 1/2, M422a, M501 and M282 work much better (more smoothly) if a small amount of lubricant (eg Molykote G-n Metal Assembly Paste) is applied to the thread. This prevents galling of the thread under heavy load and reduces, to a certain extent, unwanted rotation of the other part of the tool.

The width of rims can be measured in 2 different ways: the inside or the outside. This means that one and the same rim can be indicated both in (for example) 2.15 “and 3.08″ WM2: inside 1.85″ (47 mm) outside 2.72″ (69 mm) WM3: inside 2.15″ (55 mm) outside 3.08” (78.2 mm)      

These posters are only shown for information. We do not sell these posters. We welcome BMW posters from the pre-69 era.  Mail us at  info@salisparts.com    

By Michel Loos, The Netherlands The photos are self-explanatory. Steps:  filing  – sanding – pneumatic hammer – aluminum oxide blasting (Edelkorund) – glass bead blasting  

Cylinder black with part nr. 09122 For temperatures up to 500 °C continuous use and up to 700 °C with impact load 200 ml is sufficient for 2 to 3 large cylinders. Ideal for spraying and painting engine cylinders, exhaust systems and other metal objects subject to high heat. Classic cylinder lacquer is initially thermoplastic; in other words although it is air-drying, it becomes sticky even with moderate heat, expands and hardens again when it cools down. This process is repeated as long as the polymerization temperature is not reached. The lacquer must be heated at least once to 150-180 °C to finally cure. After
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BING jets are stamped with numbers, such as 35, 40 (idle jets) and 110, 115, 120 etc (main jets). One would expect that these numbers refer to the diameter of the jet bore, however this is not the case. This is confimed by the company BING in Germany. A few examples of main jets measured with a wire / jet gauge: BING 44-051 main jet 130 = gauge 120 (= 1.2 mm) main jet 125 = gauge 110 (= 1.1 mm) main jet 120 = gauge 105 (= 1.05 mm) main jet 110 = gauge 95 (=0.95 mm)            
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Stromlaufplan BMW R25/2

Different exhaust pipes are available in the market, unfortunately not always an exact replica of the original pipes: the shape of the bends does not correspond with the original BMW exhaust pipes as can be seen on this picture. The 2 lower exhaust pipes are identical to the original pipes.   Next to that, these pipes follow a slightly different path than the original exhaust pipes. This causes a problem for the R67 – R67/3 models: in the horizontal section, they’re not running close enough to the frame, causing too little clearance between the brake pedal and the right-hand exhaust pipe,
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This modification and upgrade, using BMW components, results in a lower-ratio gearing for R26, R27, R50 and R60 gearboxes producing smoother, robust and responsive performance especially in 1st, 2nd and 3rd gear changes while 4th gear is unchanged. The “S” gear ratios allow the rider to accelerate smoothly through gear changes by letting the motor rev freely through an optimum power-torque range. Although the 3rd gear of both gearboxes have the same number of teeth, they are different: The standard gear has a diameter of 65.6 mm and the S-type gear has a diameter of 65.2 mm. They have a
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With hardly any new carburetors being produced by BING for the < 1969 BMW mono and twin motorcycles, it’s getting increasingly important to be able to repair and recondition the used original carburetors. Luckily, special parts and tools are available nowadays to restore the carburetors to a good working condition. A. Idle mix screw: very often, the M7 x 0.75 mm screw thread in the carburetor housing is worn out. There are 2 good solutions to this problem. 1. drill the threaded hole to 7.2 mm – cut M8 x 0.75 mm screw thread – install the idle mix screw with
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electronic-voltage-regulator-bmw-r24-r26-eng electronic-valtage-regulator-bmw-r51-3-r69s-eng electronic-voltage-regulator-bmw-r27-r50-eng

By MS Motor Service (Kolbenschmidt) Click here to open as PDF: KS Installation of piston rings

Fair calender Oldtimer & Youngtimer: https://www.messen.de/de/1278/branche/oldtimer-und-youngtimer (mainly Germany) BMW forum: http://2-ventiler.de/  (Deutsch) http://www.flat-twin-bmw.com/  (French)   BMW clubs Germany: http://bmw-einzylinder.de/   BMW clubs United States: http://vintagebmw.org/v7/ http://www.bmwmoa.org/ http://5united.org/   BMW clubs United Kingdom: http://www.thebmwclubs.org.uk/ http://www.theairhead.co.uk/   BMW clubs The Netherlands: http://www.bmwclubnederland.nl/ http://www.bmwcluboirschot.nl/ https://bmwmcnnl.nl/ https://www.bmwboxerclub.nl/v2/   BMW clubs Denmark: http://www.bmw-veteran.dk/   BMW clubs Indonesia: http://bmwclubjakarta.blogspot.nl/   Facebook: https://www.facebook.com/Bmwclassicmotorcycles/ (that’s us) https://www.facebook.com/groups/bmwold/   (Vintage & Classic BMW Motorcycles USA) https://www.facebook.com/groups/AirheadsAustralia/ https://www.facebook.com/profile.php?id=100001965546450  (Richard Sheckler) https://www.facebook.com/scottiesworkshop/ (Scottie Sharpe)   Information sites: http://w6rec.com/general-bmw-motorcycle-information/ http://bmwdean.com/ http://vintagebmw.org/v7/ http://www.beemergarage.com/ http://www.bmbikes.co.uk/information.htm https://bmwr12.net/ http://www.wildstar-fan.de/BMW/home.html (R25/2 restoration- Deutsch) http://labeheme.jimdo.com/ (/5 info – French) http://www.ibmwr.org/otech/chassis.html  (Survey of Chassis Numbers) http://weissundblau.blogspot.nl/2011_05_01_archive.html (after-market hubs) http://www.earlesfork.com/ http://www.trixondrums.de/glaeser/glaeser.htm (Gläser fairing – Deutsch) https://www.shannons.com.au/club/bike-news/old-bike-australasia-1937-bmw-r5-ss/ 
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Source: Wikipedia https://www.batterystuff.com/kb/ The Lead Acid battery is made up of plates, lead, and lead oxide (various other elements are used to change density, hardness, porosity, etc.) with a 35% sulfuric acid and 65% water solution. This solution is called electrolyte, which causes a chemical reaction that produce electrons. When you test a battery with a hydrometer, you are measuring the amount of sulfuric acid in the electrolyte. If your reading is low, that means the chemistry that makes electrons is lacking. So where did the sulfur go? It is resting on the battery plates and when you recharge the
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By Richard Sheckler, Wayne, Ohio. Spot welding of panels inside the tank for strength and to plug the rust holes. The tunnel is removed to get inside. The last step before reinstalling the tunnel is to weld the knee pad brackets in place. When the tunnel is TIG welded in place, the inside is sealed with fuel resistant epoxy.  

By Richard Sheckler –  Wayne, Ohio. An R24 brought back. Scroll down for Richard’s story.         I met Garfield Smith (Petrolia, Ontario) more than twenty years ago. He mentioned that he had an R24 BMW which was made during his birth year 1949. This was also an important year for BMW, because they were in serious financial straights after WWII with the shackles of the Allied Military Command mandate not to manufacture motorcycles that could be used for making war. In 1949, the restrictions were lifted partially, allowing German firms to build motorcycles up to but not
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Overview of  BMW motorcycle models produced from 1948 to 1969 (specials not included) Click for larger image: Models & Production Numbers  

Overview of fuel cock types for 1 and 2-cylinders

Overview of ISO metric screw threads M3 – M30. Commonly used screw threads on 1948 – 1969 BMW models are M6x1 coarse, M8x1.25 coarse and M8x1.0 fine.   The length of bolts and screws is measured like this:                

Overview of carburetor nr’s and settings  

A visual inspection of the spark plugs can serve as a good indicator of the condition and tuning of the engine. This Bosch sheet may help to identify the possible cause in case of trouble. (click to enlarge)

Guidelines for correct installation of (Bosch) spark plugs  

No. 1/57, 1957

No. 1/62 (183) February 1st, 1962