bad lighting

[bazphantomf12]

so i own a malaguti phantom f-12
my lights arent very bright at all even on full revs
so i have just brought a new regulator
apparently that would fix it along with cleaning my earths
so i cleaned my earths too, started bike up today, the lights are still pretty dim
what else could this be?
the f-12 2001 uses 15w bulbs in the headlights (high beam)
and 5w sidelight bulbs for the low beam
i cannot seem to find any bulbs that will fit with a higher wattage?
what else could be causing my bad lighting problem
many thanks
baz.
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tesco trolley mong