The SU-6509 is a replacement panel air filter from K&N Engineering, designed for the factory airbox on the Suzuki SFV650 Gladius. The manufacturer says it is engineered to seal properly in the stock box, so unfiltered air does not sneak past the element. It is washable and reusable rather than disposable, and it carries K&N's Million Mile Limited Warranty. The manufacturer says it gives minimal restriction with strong filtration, and that a fully stock motorcycle does not need a fuel management system to run it. That makes it a bolt-in upgrade over a paper filter, without a tune. Search terms riders use include K&N SFV650 Gladius air filter, SU-6509 high flow airbox filter, and washable Gladius 650 intake filter.
Published fitment years differ, so confirm the application before you order. Owners on user forums describe the SV650-family airbox as a fairly simple job. Remove the seat, take out the two tank bolts at the headstock, and prop the tank with the tool under the rear seat. Then remove the airbox lid screws, which stay captive in the cover. Before reassembly, check the airbox's lower rubber gasket, since owners report the K&N's own sealing rubber can take its place. Confirm that layout on the Gladius before you start.
The manufacturer states that installing the SU-6509 on a fully stock motorcycle does not require any fuel management system.
The manufacturer's materials are not consistent: its blog describes the filter for 2009 through 2016, while its product pages list individual years from 2009 through 2015. Confirm the fitment with the manufacturer before ordering.
The manufacturer describes the SU-6509 as washable and reusable, and it is backed by a Million Mile Limited Warranty. Follow the manufacturer's care guidance for cleaning and re-oiling.
This is a beginner-friendly bolt-in job that needs a 4mm and 6mm hex bit set, a long Phillips screwdriver, and compressed air for cleaning the airbox. Owners on user forums report that the tank and airbox screws are the main time sink, and that the airbox clamps can be awkward to reach. Owners also suggest cleaning any debris out of the intake before the new element goes in. Because most forum steps come from SV650-family bikes, confirm the Gladius-specific sequence against the service manual before you start.
