silver lake sand dunes, MI

I've been there a few times when I used to live in south bend.

You will need a whip flag, spark arrestor and need to meet the DB requirement. FYI I believe the stock cr250 exhaust does not come with a spark arrestor so switching back to that won't help you out. If your muffler packing is in good shape you may pass. If it's blown out, I'd replace it. The entrance to the park is very controlled, so sneaking by won't work. keep the idle down when entering and they may just wave you through. The tests are vague at best, they guess at the rpm and are measuring sound from the side of the muffler. Supertrap style exhausts fail more often because the sound comes out the sides. You can have your bike sound tested at your local BLM office, or possibly a local dealer.

In my experience at various races, most of the 2 strokes pass the sound check and most 4 strokes don't. (without choked down exhausts and quiet cores installed) It's wierd the EPA seems to prefer 4 strokes and the BLM rules favor 2 strokes.

Honestly there are alot of dune buggies there that wouldn't pass if they were propery tested.

Not sure about the level of enforcement at Silver Lake, but here is what I do know:

You will need an FMF Powercore Silencer/Spark Arrester in order be below 94 DB. You will also need to keep it freshly re-packed -- full with insulation, but not too tightly wound as 94 DB is *very* hard to achieve with a motocross bike.

I believe my 1997 CR 250 was around 92 db or so at the Mounds several years ago. The ranger there was in disbelief as very few motocross bikes are able to achieve this.

The Powercore seemed to shift the powerband down-ward in the RPM range with little if any power loss. It's the only silencer I use -- even for MX.

never checked

been there 50 times never been checked, they toss a stick in silencer to be sure no mods tryin to get by with visual inspect. unless you got some ridiculously raced out machine they will not check. if you do, get your flags installed, orv's on truck and ride,, and dont bring booze .they check ur sparky, and you drive ur truck in the dunes. they could care less. they will not have you get out of your truck to start your bike.