Graves Motorsports Smog Block-Off Plugs- Yamaha R1 (1998-2003)

 
• Graves Motorsports Smog Block-Off Plugs are designed to seal off the ports on the cylinder head used by the air injection system (a.k.a smog pumps or AIS).
• Once these are capped off the air injection system can be safely removed. These Smog Block-Off Plates are made from machined aluminum. Set of four.
• There are two reasons why you want to remove the air injection system from your bike:

1) if you are using your motorcycle on a closed course (racing, track days, etc.) you will want to remove all unnecessary equipment from your bike for reduced weight and ease of maintenance.

2) to get an accurate Air:Fuel (A/F) ratio when “dyno”-ing the bike. The air injection system pumps fresh air directly into the exhaust stream in order to burn off any unused fuel. Unfortunately by doing this, the A/F ratio is thrown off by the extra “fresh air” in the exhaust stream. By removing the air injection system you can achieve an accurate A/F ratio