Technical Service Bulletin Chain Sprocket Support

Subject: Chain Sprocket Support                      Models: 911 1980

Bulletin Number: 80 – 02

Modifications during 1980 model year:                                                                  Retrofitting earlier cars

support imgs

(as of Engine No. 930/07.640.0451) New parts can be installed in earlier cars as follows:

  • Install chain tensioner, Part No. 930.105.053.00 and add sprocket support, Part No. 930.105.509.00/510.00, together. (Previous chain tensioner, Part No. 930.105.049.00 cannot be used with new sprocket support or vice versa)
  • Use either new or old chain housing; however, when installing new sprocket support into old chain housing, part No. 930.105.061.00/062.00, upper chain tensioner support shaft in housing must be polished with a fine polishing cloth


Both new and old parts are available as replacement parts.

  • Chain sprocket supports have wider bearing (1)
  • Upper mounting boss (3) on chain tensioner has been narrowed
  • Upper mounting shaft (4) in chain housing is now polished.
I      Chain Tensioner930.105.049.00930.105.03.00
II     Chain Sprocket Support, L.        Chain Sprocket Support, R.901.105.505.02 901.105.506.02930.105.509.00 930.105.510.00
III    Chain Housing, Left         Chain Housing, Right930.105.061 930.105.062.00930.105.061.02 930.105.062.01
Note: Bushing in chain sprocket support is not available as a spare part.

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