Gregory Bender

Distributor disassembly, bearings, and O-rings

Moto Guzzi V7 Sport, 750 S, 750 S3, 850 T, 850 T3, 850 T3 California, V1000 I-Convert, V1000 G5, 1000 SP, Le Mans, Le Mans II, Le Mans CX 100, Le Mans 1000, 1000 SP III, 1000 S, California II, California III, California 1100, California Jackal, California EV, California EV Touring, California Aluminium, California Titanium, California Special, California Special Sport, California Stone-Metal, California Stone-Touring, California Classic, California Touring, and California Vintage models

Created:

Updated:

// //

Thanks to Charlie Mullendore of Antietam Classic Cycle for sending me the following information and photos on how to disassemble the distributor to replace the bearings and O-rings. In Charlie's own words:

Last night was the first time I've ever needed to disassemble a Tonti distributor. Lots of oil inside and all over the outside, so something had to be done about it.

I figured it used a felt seal similar to the Loop distributor, but it's completely different. The shaft runs on two 6001-RS1 sealed ball bearings and there are two O-rings on the shaft, one O-ring at each bearing to seal the shaft to the bearing. The O-rings were hardened and sacked on this one, so no wonder it leaked. Just eye-balling it, the O-rings looked to be the same size as those for the cylinder studs. Sure enough, they seem to fit perfectly.

Thanks to Jack Huisinga for sending me this additional information about the :

Replaced in distributor. This Distributor is a Marelli S311B. The shaft is supported by two double shielded bearings. The shaft has two slots cut into it so that the seal between the inner bearing bore and the shaft. The that fits is a 9.25 mm × 1.78 mm

Moto Guzzi Tonti distributor, bearings, O-rings.
Moto Guzzi Tonti distributor, bearings, O-rings.

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.

Moto Guzzi Tonti distributor, bearings, O-rings.
Moto Guzzi Tonti distributor, bearings, O-rings.

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.

Moto Guzzi Tonti distributor, bearings, O-rings.
Moto Guzzi Tonti distributor, bearings, O-rings.

Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.