yeah, it blows out after awhile. it also seems to deaden the noise a lot better while it is in there. I've also used Kaowool, which is like a furnace insulation stuff, that works really well, and i've used those celing tiles that are made of like hardish compressed insulation wrapped in a tube... that works pretty good too. If you dont mind repacking it every 500 miles or so, house insulation does the job, is cheap (probably free) and results in +3 hipster cool points for using non-moped-parts on a moped.
also, all that packing stuff loads up with oil way before it blows out, so you should probably be changing it every 500-1000 miles anyhow.