GU90706090 Heat tolerant Viton cylinder stud o-ring, used on all big twin 700, 750, 850, 1000 and 1100cc engines from 1967 to 2010. Generally 12 areused per engine. 1 on each of the 6 and 12 o'clock cylinder studs,between the base gasket and the cylinder. Then 1 on each of the otherfour studs between the cylinder head and the rocker arm carrier assembly. Note beveled recess in the mating surfaces shown in the photos - one oring fits into each of the recesses.
Exceptions to this rule are on the 4 valve per head Daytona 1000, Centauro, Daytona RS, MGS01 models, as well as the Breva 1100 and 1100 Griso, where the o ring is only used on the studs between the cylinder head and the carrier assembly. This oring is also used to seal the fork bottom bolt on 750 Nevada from 1992 to 2001.
Substitute number 90706090 GU90706090
Model list: V700, V750 Special 1969 to 1971, Ambassador, 850GT, Eldorado, V7 Sport, 750S, S3, 850T, 850T3, 850T4, V1000 Convert, V1000 G5, 850 LeMans, LeMans II, CX100, SP1000, SP II, SP III, Strada, LeMans III, LeMans 1000 all years LeMans IV and LeMans V, 850T5, Mille GT, 1000S, California II, California III, California III injected, California 1100, EV, EV Touring, Jackal, Bassa, California Special, Special Sport, California Stone, Stone Touring, Aluminum, Titanium, Stone Metal, Quota 1000, Quota ES1100, 1100 Sport carb, 1100 Sport injected, V11 Sport, V11 LeMans, Rosso Mandello, Nero Corsa, Scura, Tenni, V11 Cafe Sport, V11 Sport Naked, Ballabio, Coppa Italia, California Vintage, Black Eagle, Daytona 1000, Centauro, Daytona RS, MGS01, Breva 1100, 1100 Griso.