It takes a little more care with our F800S/ST as the filler opening and amount of fuel stabilizer treatment added are both small. For better mixing, the less fuel initially in the tank, the better. Add the correct amount of stabilizer. Fill the gasoline at the full speed flow rate to increase the agitation. Why bother? Easy. The F800 twins have a non recirculating fuel system . . . . there is no fueltank return hose that immediately aids in the complete mixing of owner additives when the engine's running. There's only 1 high pressure fuel line and the under seat finned fuel control computer varies the pump speed to maintain that fuel pressure. That means any carelessly added unmixed fuel stabilizer concentrate might settle at the tank bottom just the way Italian dressing separates to several distinct levels. That concentrated tier of stabilizer in gasoline will be drawn in just that way, decreasing the strength of the intended mixture. It may or may not do any harm when that happens, but it will diminish the stabilizer's intended full strength mixture ratio.
It's a little thing, but one we should be aware of, even if you are not the fussy type.
BTW, in the cold weather my bike runs terrific. Only drawback is the much lower instantaneous MPG readings until the engine is hot. A much warmer ride than the 50R was because of the front fairing and windscreen. Thermostat controlled water cooling with full time oil/water heat exchanger flow means the engine oil gets up to full operating temperature quickly. Even when it's very cold outside and the cruising RPM's are not high. Cool.
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