Looking for a magneto for a 1955 R69. I was told a R68 will also fit. The inside of the magneto where it fits over the camshaft should be about 1 3/8" deep. The other mags for the R60's etc are about 1" deep. It's also 17mm. Any help will be greatly appreciated, Thanks! Another easy way to tell the difference in the rotors. The R69 - R68 magneto rotor - the shoulder that goes into the oil seal is about 3/8" wide. The other rotors are 3/4" wide. Thanks for your help!