I have been wondering what my saw should tach. at now that it breathes better. I removed the tube from the muffler and increased the area by 65%+/- as well as put holes in cat 3x3/8" . So after I unchoked my 2152 and richened it up to gurgle/4stroke by ear I was wondering what the rpm's should be, stock top is 13,600 and it was 13,167-13,204 before (at last checkup last year) now it rips but it seems like the rpm's are lower to my ear. I consistently ran 91oct plus booster to 100++and amsoil interceptor since it was new at around 40:1/48:1 . I am currently running 100 oct and 36:1/40:1 to be safe till I can figure it out to where I want it. What is a good tach. number after modification? Where is a good cheap place to find a tach?