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Graves Motorsports Smog Block Off Plate Honda CB300/CRF250/300 AB014

Graves Motorsports Smog Block Off Plate Honda CB300/CRF250/300 AB014

Regular price $29.95 USD
Regular price $29.95 USD Sale price $29.95 USD
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Graves Motorsports Smog Block Off Plate for the Honda (multi fitment see below). Graves Motorsports Smog Block Off Plate are designed to seal off the ports on the valve cover used by the air injection system (a.k.a smog pumps or AIS).

Fitment:
  • HONDA CB300F 2016-2018
  • HONDA CB300FN 2021-2022
  • HONDA CB300R 2019-2021
  • HONDA CBR250R 2011-2014
  • HONDA CBR300R 2015-2023
  • HONDA CRF250L 2013-2020
  • HONDA CRF250RL 2019
  • HONDA CRF250RL (Rally) 2017-2018
  • HONDA CRF300L 2021-2023
  • HONDA CRF300L Rally 2021
  • HONDA CRF300LR 2021-2023



The air induction system (AIS) burns unburned exhaust gases by injecting fresh air (secondary air) into the exhaust port, reducing the emission of hydrocarbons.

Once these are capped off the air injection system can be safely removed. These Smog Block Off Plates are made from CNC'ed billet aluminum and feature the Graves Motorsports "G" logo. There are three 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 dynoing 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.
  • 3. This addition will typically remove the majority of popping on deceleration that can be experienced with un-burnt gasses within the emission charcoal chamber. Note: Proper tuning may be needed and this is general feedback.
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