The K&N YA-2509 is a reusable, cotton gauze panel filter for the Yamaha XT250, sized to drop into the stock airbox. The manufacturer markets it as a high-flow powersports engine filter, with a 1 year limited warranty listed on its spec sheet. Because it is washed and re-oiled rather than replaced, the higher upfront price is offset over time against repeated disposable-filter purchases. Owner feedback on user forums is mixed. One owner reports a smoother throttle response and no jetting changes, while a rider on an XT250 forum reported rough running after fitting a K&N, so expect results to vary. Searchers looking for a Yamaha XT250 K&N drop-in, XT250 reusable air filter, or XT250 airbox filter upgrade will find this listing relevant.
The manufacturer lists the filter at 5.188 in long, 2.688 in wide, and 1.063 in tall, weighing 0.4 lb, with a re-oiling amount of 0.12 oz (4 ml). Its product page lists fitment for the 2009 through 2013 XT250, while its XT250 category page lists applications from 2008 through 2025, so confirm your model year before ordering. For DIY owners, the job is a filter swap inside the factory airbox, not a housing modification. Seal the filter edge carefully, since owners on user forums note that uneven airbox surfaces can leave gaps, and the manufacturer's recommended fix is a thin layer of non-petroleum grease around the sealing edge. Any gap lets unfiltered air reach the engine.
The manufacturer's product page lists the 2009 through 2013 Yamaha XT250, while its XT250 category page includes listings from 2008 through 2025. Confirm your bike's model year with the manufacturer before ordering.
The manufacturer's research sources do not state a jetting requirement. Owners on user forums differ: one reports no jetting changes were needed, while another described rough running after installing a K&N on an XT250 and reverting to the stock filter. Check with the manufacturer if you plan to alter fuel settings.
The filter is designed to fit the factory airbox, so installation is a filter swap rather than a modification, but the manufacturer's install guidance for this model was not located in my research, so confirm the airbox access steps for your year in the owner's manual. Owners on user forums recommend removing the airbox cover carefully and noting the filter's orientation before removal so it goes back the same way. Apply the non-petroleum grease around the sealing edge, reinstall the cover, and confirm it is fully latched. Avoid working on a hot engine.
