2001 cr 125 set up(have you seen this yet)?

[thewbomb]

ok whats the deal with this set up........2001 cr 125 with a 95 cylinder. The carb is set up for a 250 with the stock needle, 35 slow and 390 main.......this was a race bike and i can't seem to find the mechanic that worked on it to ask him why the set up was like this.......oh yeah there is a knocking sound coming from the top of the cylinder but everything is new or rebuilt on the bike......can someone tell me why the set up is like this and if i change the carb specs will it mess the power up or uncompliment the 95 cylinder??????????

 

[marcusgunby]

It was a hot setup for the 01-the 01 cylinder and pv is not avery good mx design -so people went back to the 95 top end.Sometimes new cr pistons are a loose fit and cause a rattle.