Instructions for Cylinder black (Einbrennlack)
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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Solving hard-start problems by Craig Vechorik
Click this link: http://www.benchmarkworks.com/articles/tech/hardstart.html In addition: The resistance across the two spark plug leads on the ignition coil is usually 11 – 12 K Ohm (original coils and new “made in Germany” coils). Some after-market coils have a resistance up to 20 K Ohm. When the magnetic field of the rotor is still OK, this higher resistance will not necessarily cause a problem. A weak spark at the spark plug can have different causes: a broken or poor quality ignition coil is one of them. When the insulation (schellac) within the coil is damaged (crazing), the internal windings will short circuit,
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Replacement for Matra 513 tool – rear swing arm pivot pins
The rear suspension pivot pins of the R26, R27 and R50 – R69S models can be adjusted with the use of the Matra 513 tool. However, no replicas are made of the Matra 513 tool. The alternative is a pin wrench such as PN 31421234399.W (Pin wrench for front fork cap screw R69US, R50/5 – R100) Although the diameter of the pins is just under 4 mm and the holes in the pivot pins are 5 mm, this tool functions well. The alternative is pin wrench 31422000243.W (Pin wrench for front fork cap screw R25/3): the pins have a diameter of just
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BING jets
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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Carburetor flanges
The Bing carburetors used on the R51/3 to R69S models came with 3 different flanges. We sometimes get the question: can I put carburetor X on BMW model Y? In theory you can put an R51/3 carburetor on a R69 engine and even get the engine running, but you will quickly discover that the air pipes won’t fit. These images are self explanatory Modified carburetors can be found in the market that fit the R68, R69 and R69S cylinder heads. However, there are some differences from the original models, most notably the carburetor flange:
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Matra 282 tool
We mill 2 planes on the threaded bushing so that it is possible to use a 22 mm wrench on the threaded bushing. This is necessary in cases where (for instance) the crankshaft bearing is glued to the bearing journal, to prevent the threaded bushing from rotating while tightening the central bolt
Cylinder heads R50 – R69S: butterheads and LK heads
Very informatieve article by Duane Ausherman on “butterheads” and LK heads: http://www.w6rec.com/duane/bmw/head/
Breather plates on the R51/3 – R69S engines
3 different breather plates have been used on the boxer engines:
Exhaust pipes
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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Transmission upgrade/rebuild to “S” gearbox ratios
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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