I run pods on mine. The older RS 250's and 125's I've seen do not run any type of air box so I'm not to sure of their importance unless you have the cool guy ram air. I also cut the top off my airbox before I got my RS carbs and pod filters.
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1995 A kit TZ 250
1994 Rothmans NSR 300sp SOLD
1998 RM 250 freestyle/motorcross
1998 Meathanol burning CR 500 AF super retard/motorcross/sand dunes/play bike