knelson

Sure, It's harder to hear with larger pipes such as shearer's or CPI's, than Toomies or FMF's. You will deffinately hear the rattle though.It sounds like shaking a can of spraypaint, I've used this little tool on everything from 2 stroke BigBore tripple Dry-pippied jetskii's (best 82.8mph@7160rpms) to worked-over 2 stoke 2.5 mercs(best 9300rpms@123mph), I usually use this in conjunction with a EGT gauge for 2 strokes or my Innovate wideband for fourstrokes. My current one is made out of a stethoscope, but the homemade muffs worked very well and keeps your ears warmer!

Here is how I detect deto on motors that are loud.Take a 1/2 dia. or so copper tubing about 3 inches long and mash the one end closed to about 1in up. drill a 3/8 or so hole through the side that is mashed flat. Take a head nut off, bolt copper tubing down. on the other open end of copper tubing connect a hose (I use tygon, any flexible hose will work) that will run to a set of earmuffs that you drill a hole through and connect hose to.

I would probably do a little more investigating