I've been trying to get some more bottom end out of my YZ 125 and this is what I have added:
1 tooth to the rear sprocket, Mossbarger torque spacer (MikeT - they cost around $25 and yes, they go between the reed cage and cylinder), Boyesen Pro-Series 2-stage carbon fiber reeds, and a PC shorty silencer (and have rejetted the bike and reset the carb float level).
These mods have helped some, but I still might try another tooth on the rear...
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'01 YZ 125 - #32
2000 D17 Women's Motocross Champion
Sponsors: DGY, MX-Tech, Bell, Smith, Works Connection, Boyesen, Twin Air, SoCal/DeCal Works, Morris Trailer Sales, and Skyway Trucking
[This message has been edited by nikki (edited 04-16-2001).]