K&N Engineering, of Riverside, California, is the inventor and leading innovator of reusable K&N cotton gauze filter technology for automotive applications. Including for the Yamaha Road Star. From humble beginnings as a family run business over 35 years ago, K&N Engineering, now a truly global company with offices in the U.K. and the Netherlands, K&N continues to exist as a family owned business with an enthusiast mindset and a direct connection with motor sports that carries over throughout all levels of management and manufacturing.

Today, K&N exists as both the sales and brand leader for performance filters, and maintains a stocking catalogue of over 3,500 part numbers, including an extensive line of both factory replacement drop-in filters, FIPK (Fuel Injection Performance Kit) applications, and its line of innovative Performance Gold oil filters.

Air Cleaners filters system for motorcycles Document Type and Number:United States Patent 4648474

Abstract:  Air Cleaners filters system for motorcycles employing the hollow interior of a main frame member. A U-shaped cavity facing forwardly of the motorcycle in the fuel tank allows access to the air cleaner filters assembly positioned within the main frame member. An inlet opening is provided on the upper surface of the main frame member while outlet openings on the lower surface thereof extend to carburetors. The inlet opening of the main frame member is reinforced and a baffle is positioned between the air filters assembly and the intake passages to the carburetors.

Custom Air Filters for Metric Cruisers - K&N Custom Performance Air Cleaners filters offer

  • good looks with awesome airflow.
  • Machined from billet aluminum, each air cleaner filters is luster polished, then chrome plated to compliment any show bike.
  • Your motorcycle may need adjustment to the carburetor or fuel injection system

According to author enthusiast, Art Friedman, this is what he says about the Yamaha RoadStar:

The surprise with the new Yamaha Road tar isn't that its engine has been updated and enlarged to 1670cc using components from the Warrior. We expected that. The surprises are how much more solid that extra 68cc makes the engine feel and the other changes Yamaha made to the bike and some it didn't make.

We spent most of a day riding the an early-production 2004 RoadStar for this report, and came away impressed by the changes which are both more subtle and more impressive than our first glance at the bike would have suggested. We will have a complete test for the October issue cover story in Motorcycle Cruiser magazine.

We expected that Yamaha would incorporate fuel injection when it rolled the technology from the Warrior into the RoadStar. Instead, it stayed with a single 40mm carburetor, apparently because customers said they preferred the simplicity and tuning ease of that configuration. Of course, that also helped keep the price down, part of the reason that the Road tar, now nominally a 1700, comes in at the same price as the original 1602cc version.

However, the new bike has a redesigned airbox with more capacity, which apparently improves breathing. They have also juggled reciprocating masses in the pushrod valve train and beefed up some of the structures that support it to let the revised engine rev a little higher and get into the rev limiter a bit more gently than the previous version. With longer cam duration, higher compression, shorter-skirt pistons, and dual plugs in addition to the additional 68cc (which pushes it above the 100-cubic-inch mark), the bike feels noticeably stronger off the line. Cylinder fins have been revised for better cooling too.

The most pleasing difference is up top, where it runs out of revs more gently and pulls longer before you need to shift. In addition, they gave the 1700 a taller first-gear ratio then dropped the overall ratio slightly, which puts all the gears closer together. These changes make the first-to-second shift less of a jump and eliminated our tendency to bump into the rev limiter in first. Because the engine revs higher, the slightly higher engine speeds on the highway are not at all troublesome, even if you notice them. With horsepower and torque increases of 15 percent or so, you get crisper passes at highway speeds.

The character of the engine is virtually unchanged, however. It feels, responds, and sounds the same. The drivetrain remains admirably free of lash, and once the engine is warm, throttle response is splendid. Shifts are positive and light. The final drive belt is stronger yet narrower. Despite the added displacement and power, the 48-degree engine continues to defy convention, refusing to vibrate significantly despite absence of a counterbalancer. Only up near where the rev limiter comes into play does vibration become an issue.

Shop now for other K&N Air Cleaner filters for the following motorcycles:

  • Harley Davidson Touring Motorcycle-K&N Air Charger  
  • Harley-Davidson FLHR Road King air filters by K&N
  • Harley-Davidson FLHRC Road King Classic air filters by K&N
  • Harley-Davidson FLHT Electra Glide Standard air filters by K&N
  • Harley-Davidson FLHTC Electra Glide Classic air filteres
  • Harley-Davidson FLHTCU Ultra Classic Electra Glide air filters
  • Harley-Davidson FLHX Street Glide air filters by K&N
  • Harley-Davidson FLTR Road Glide air filters by K&N