The stock carburettors on 850 Nortons, from 1973 to 1977, were a pair of Amal Concentric 32mm units, the 932 series.
You can use either a single Mikuni VM 34 or VM 36 on the 850. The 750 uses only the 34.
Norton Commando Engines at the End of Production in 1976 was 850 cc. Triumph Boniville Engines at end of Production in 1984 was 750cc.
The PH 3600 is one of Fram's most popular filters and fits at least 50 vehicles of all kinds. It's easier to name your vehicle and we can tell you if this fits it or not.
850
850
28.5% of 850 = 28.5% * 850 = 0.285 * 850 = 242.25
36% of 850= 36% * 850= 0.36 * 850= 306
48% of 850 = 48% * 850 = 0.48 * 850 = 408
4% of 850 = 4% * 850 = 0.04 * 850 = 34
850 and 850. If they have to be different, 850 and 1700.
850 and any multiple of 850. Any multiples of 850 that differ by 850.