After riding 165 on track for about month now an loving it .I got to spend time on bigger track that I would say was a four stroke track lots jumps close on exit to corners. This thing rocks I found what I thought was good suspension poor .I am going so much faster now with less effort an I reach limit of suspension .yes the high rpm is not there but not bad but the bottom an mid pulls****************************************!! Maybe try diff pipe but this works . Mine might be diff than some I have Fbf cylinders to start with an compression is 217 so it's race gas only . Thanks Walt An by way I have one of nicest 2002 cr250 in garage low low hrs that's for sale now after I built 165 .