For first timers and noobs... you can't fail to be entertained (at a normally run meeting) just for the spectacle of 4 riders blasting around on 500cc bikes with no brakes. It's only when you've been to a few and that initial awe has worn off that you suss out that this really ain't very good at all... but if you stick at it you'll see a belter of a meeting, or a consistently winning team, that might keep you coming back for more.
Define young fans... most "young fans" I've seen at Speedway couldn't really care less what's going on out on the track, they're normally just running around in circles causing a nuisance to everybody, but who cares the parents can come along and the kids only cost a quid. By the time the older "young fans" have developed an actual interest in the sport they are fast approaching a 2000% price increase and when they hit that they are lost to the sport for the next 20/30 years or so while they're out chasing boys/girls and drinking themselves into a stupor and maybe getting into other more mainstream sports.