Patternflyer1,
You have gotten great tips from the YS user community on troubleshooting your L's running condition. Have you tried posting this condition in the YS forum? There you will receive responses directly from Dave Shadel of YS Performance the US importer and service center for YS motors. I have provided the link below to the RCU YS Forum.
http://www.rcuniverse.com/forum/YS_E...mid_197/tt.htm