Just some info on a couple of nice new silencers produced by the locals. The HPD MT "Quiet" silencer, and the Hot Seat, spark arrestor equipped silencer. Both have great fit and finish....both do their best to tame the race-mod 400.
The db tests were performed on a HPD race-mod, equipped with the new style ATV8 pipe. All readings were taken at 20" and 45 degree angle to the silencer outlet. Both silencers were equipped with 2 each kevlar silencing bands (HPD units, originally meant to quiet the pipes, have found they knock a couple of db's off the silencers too).
The 3,000 rpm reading is a standard that most DNR's use as a 50% of the machines max rpm. (that's stock)
HPD MT- idle=90db........3,000rpm=98db
Hot Seat-idle=92db.......3,000rpm=99/100 reading was fluctuating.

Gonna fab a "spark arrestor" for the HPD unit and run it at Silver Lake.

Ken

 

modquad,

I see you didn't test my silencer. I am running a YZ250 FMF Shorty. Mostly because it is a little quiter than the silencer that is supposed to be on the RCR pipe I am running. Doesn't seem to be much performance difference between the two.

By the way, what happened to the 700 belt? Did you burn it up or did it break? I am running HPD's belt now. But I'm still not convinced that it is better. Those stock Polaris belts sure are sticky when they are new. That only lasts for about fifteen minutes thou.

 

Elroy, I've got an FMF Turbine Core, I can give it a meter reading. As I remember though, it was louder than either of the two I tested.
The 700 belt basically overheated, then began delaminating. Like I said earlier, I made sure everything with the clutches was true to the world. The higher RPM's must have taken the toll.


Ken