I bought one, and older model off a guy who used to race raider 1100's. He said that he used this tach, but when i tried it on mine, i got good low rpm #'s and crazy hi rpm #'s. The directions say that it is only good for 1 & 2 cylinder 2 & 4 stroke engine. Is there a trick? I assume that if you run it in 1 cyl, 2 stroke mode that it would be accurate, but maybe i need to place the pickup clip somewhere special? Any help is appreciated.