| Short answer mate, don't use 'em! The undertank filters are a known performance decreaser. The best option is to retain the filters in the airtubes. Even the factory race bikes used filters in the tubes - when they used filters at all.
You can replace the stock ones with Pipercross which are more free flowing but still do as good a job of filtering. And they're much cheaper than the undertank jobs.
Hope that helps,
Neil. |