At the monthly meeting of Northern Colorado Trail Riders http://www.nctr.net/last night, we measured the db level of the bikes that were present.

The procedure was to first look up the testing RPM for a given bike in a chart. The KLX250S wasn't listed, so we went with the RPM for a KLX300, which was 3500RPM. Many of the dirt bikes didn't have a tachometer, so they had a mechanical "tach" which had a spring which would resonate at a setable RPM. This device, which looked like a hockey puck, was then held against the bike like on the seat or engine shroud. I read on my tach that is resonated at 3700 RPM.

The meter was then held about 1/2 a meter away from the tail pipe (measured using a string) and a reading was made.

My bike, with a Muzzy exhaust (quiet core and screen inserted) came in at 91.5 db.

I got to see a (plated) 2008 KLX450R and it was the quietest bike there last night at 86 db (still running a stock exhaust). The loudest was a KTM450 at 94 db.

I'm told, that as a group, the club has been getting quieter. Next year, a new Colorado law will be enacted to limit vehicles in the backcountry to 96db or less.

 

Thanks for the info, Dan. It's good to know where we stand legally with our aftermarket systems. A lot of us use the Muzzy in the same configuration as yours. I wonder what a stock KLX 250 would do?

Bill Dragoo
Norman, Oklahoma
KLX "250"
Dyna Sport

 

Wow, that KLX450R really is quiet. That's the future, IMO. Good on Kawi for setting the standard - everything I've heard about it is that it still makes great power, even with the quiet pipe.

 

+1 to quiet..

 

Not to be a spoil sport but seriously, how often is any of our KLX's running at 3500 rpm? On the steering neck on the frame I think the stock exhaust is tested at 7000 or so rpm..........I may be wrong though, I'll have to check tomorrow. When I'm running down the road in 6th gear at 45 the tire hum (rear Trackmaster, front 776F) far exceeds my exhaust note. Above or below that and its just the opposite. When we were in NJ a Muzzy with quiet core tested in at 100+ db, I have no idea what Jsac's bike would have been but it was the loudest one I heard all weekend with the BG on it.


Just another humble KLX-er's opinion.....carry on

 

yes i just heard of that law today. i think it is good because the aftermarket companies that sell these pipes are not even alowed to sell them by law they just do not inforce it. that is just my opinion it is really getting out of hand.

 

and after reading a magazine test they claim that if you mod the pipe you loose power and the broad spread of torque the bike has.