First step ...
change the fuel filter. They are consumables like oil filters ... I take a spare where ever I go.
I take this as be intermittant .. note the exact circumstances of when it occurs.. tank fuel level, engine cold/hot, bumpy roads, rev counter dies but motor still going via gear box, for example.
Could be anything without a good description of what and how .. maybe with some further testing ..
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S