I have a 250ex and i was wondering if it was bad for the bike if i ride without the spark arrestor in

 

no you should be fine.

 

It hurts you though.....No backpressure from the exhaust.So you'll actually be hurting it cause I put mine back in.If you want some no dollar ideas fr a 250ex....take off the airbox lid...take off the snorkel....you could also revers the front rims but it hurts the tires but gives it a wider stance.