Using the bicycle lane is illegal AFAIK.
But filtering up to the light isn't. I don't see how it makes a difference whether there's 1 lane or 2.
I completely understand the temptation, but using the bicycle lane is idiotic. Never split/filter where motorists and pedestrians would never expect you. Never split between moving cars and parked cars. You're invisible enough as it is. Even bicyclists get "doored" by parked cars. Add a motorcycle's speed and weight to that and it's a big deal.

