The contact clearance was reduced from 0,4 to 0,3 mm, according to the Technical Bulletin No. 55 of December 1954.
The spark plug air gap was reduced from 0,7 to 0,4 mm in the same Technical Bulletin.
Due to these changes ignition dropouts should vanish under all riding circumstances.
All the changes were valid for the serial production from December 1954 on.