Uncorking the Honda XR650R per Factory Tech Bulletin on 4Strokes.com

This Tech information is for modifying or uncorking the Honda XR650R Big Red Pig (BRP) for higher performance and is per a Honda Tech Bulletin. Although intended for early 2000 model Honda XR650R's, this information may also be beneficial or useful for other XR650R model years.

To obtain higher performance from the Honda XR650R you must change the intake manifold, exhaust core or spark arrestor, and change the carburetor settings by changing the main jet and jet needle (additional mods below). Be sure to remove both air intake restrictors per the diagram below with these modifications. The following table lists the Part Description, Honda Part Numbers and modification Instructions required to uncork the BRP.

Part Description

Competition Spark Arrestor

Carburetor Insulator

Main Jet (#175)

Jet Needle

Jet Needle Clip Position

Airbox Inlet Duct Caps
(Air intake restrictors)

Honda Part Number

18317-MBN-640

16211-MBN-640

99101-357-1750

16012-MBN-641

N/A

Instructions

Replace existing spark arrestor with this part.

Replace existing carb insulator with this part.

Replace existing main jet with this part.

Replace existing jet needle with this part.

Set jet needle in center (3rd) position.

Remove caps per this diagram.

Additional Jetting Changes

In addition to the above carburetor changes, Tim recommends changing the pilot jet to a 68s (Honda P/N: 99105-MBN-0680) for anyone that rides from sea level to 3000' above. This should also help to alleviate any overheating at low speed if you may be experiencing it. Credits: Tim Sweeney

The Fine Print: This modification information is provided exclusively for preparing the Honda XR650R for closed-course competition only. For additional procedures and adjustments, please consult your service manual. All jetting recommendations are based on an unmodified engine and may require changes based air temperature, humidity and altitude. In California, modifying the emissions systems of any green sticker motorcycle is considered tampering with and is prohibited by and punishable according to California state regulations.