5-speed-gearbox-repair,-racing-23-001-77-1023r-877

( ( Service-1n formation BMWM OTORRADG MBB Motorcycles R60/6-R100RS Munich, Aug. 77 Service Technic R-VK-10 wb/ur Gearbox 23 001 77 ( 10238) For U.S. and Canada only Subject: Repair Hints on 5-Speed Gearboxes and Technical Data on the Racing Gearbox Dear Dealer, Constant research and development produced improve ■ ents in the production of the 5-speed gearbox. The following is a summary of these improve ■ents and suggestions that could be incorporated in future repairs. In addition, you will find infor■ation covering the racing gearbox ratios. Latest production of gearboxes have the following changes: a) Strengthen sliding gears, identified by the 1 – narrower shiftertork groove new 5.7 ma wide old 6.5 DIDI wide b) Square, undercut dogs and windows on:;, 4 and 5 gear {to prevent possible jumping out of gear). . c) Selector Bracket: Detent ai ■ spring 23 31 1 234 791 with 5 windings, to strengthen gear selection and positive resting in each gear. Reversed pattern on rear camplate, to achieve easier selection of ueutral, the seal rings on the ca■plate spindles were left out. Result= quicker selection of neutral and easier gear selection. d) Gearbox Casting: Bigger stronger boss to allow ■ore support for the selector fork shaft, 3 and 4 gear, allowing this shaft to be lengthened by 5 •• new 105 mm ·long old 100 m■ long This improved casting is recognized by a different casting seam. -2- Kenntnis genommen – Pris connaissance – Noted – Tornado nota – Preso conoscenza I Ablage – Archives – File – Arch1vo .•:.-, …. ·1•· – 2 – If any gearboxes are to be repaired for the above reasons, use these new improvements which are interchangeable and the following hints and tips: If shifting or gear selection is hard, the cause is primarily the detent spring; ensure this spring does not coil bind when moving over the cam lobes. Shifter fork guides must slide easily in camplate tracks. Deburr when necessary. Check that all parts mounted on to the selector bracket move freely without any tension or binding. In an assembly the selector pawl should not rub against the large camplate (1, 2 and 5 gear). Straighten if necessary. The use of extra force to shift the gearbox could also be caused by worn or rough selector fork shafts, check and polish with fine emery cloth. Another major cause of shifting is also the incorrect end play of the shafts. Each shaft must spin free and end clearance must not exceed 0.1 mm. A special tool (plate) will be available soon to make ( this task easier and more accurate. Racing Gearboxes A special ratio gear set has been developed for active sportsriders or competitors. The different closer ratio is between 2, 3 and 4 gear only, thereby reducing the loss of rpm’s when selecting the next higher gear. The first gear is also higher, therefore it is not advisable to use this racing-ratio for normal use, because the clutch is used harder if the first gear is higher. So keep in mind this is strictly a racing gearbox, designed for the enthusiast. Internal Ratios Racing Standard 1st Gear 3.38 4.40 2nd Gear 2.43 2.86 3rd Gear 1.93 2.07 4th Gear 1.67 1. 67 5th Gear 1. 50 1. 50 Complete racing gear sets are available under Part No. 23 21 1 233 427. Yours truly, BMW M0T0RRAD GMBH Munich