TTR250 Sound Check

[mpsuda]

I see that inorder to ride the Michigan trails that a bike needs to be 94 dB or less. Has any TTR250s passed with after market pipes? Would the stock pipe pass without the baffle? It does not seem that loud without the baffle. I am currently running a FMF megamax with the quiet core and only 6 disks.

Thanks,

Mike

 

[BadgerMan]

Where did you see that requirement? I am very curious because although my bike is not terribly loud, I know it won't measure 94db or less. Is the forest service or dnr going to start checking bikes?

 

[KTM Mike]

I think that is simply part of MI law for legal off road riding (along with spark arrestor). I know that the CCC requires sound checks before their trail tours. I have heard of a very few instances of DNR checking bikes to...

 

[MWEISSEN]

Bman, it's been on the Michigan law books since the "closed unless posted open" law went into effect for the Lower Penninsula.

Surprisingly your setup will pass the sound check. Andy's bike passes with 5 disks.

We're heading to the CCC ride this w/e, we'll see if it still does!

 

[Smit-Dog]

Originally posted by MWEISSEN
Bman, it's been on the Michigan law books since the "closed unless posted open" law went into effect for the Lower Penninsula.

Does anyone know around what year this law went into effect?

 

[BadgerMan]

The law went into effect in the early nineties if I remember correctly. I heard a rumor recently that there is some legislation in process that would change the “closed unless posted open” law and give bikes the same rights as snowmobiles (including the use of public road shoulders). Sounds too good to be true however so I suspect that it was just a rumor.

As far as the sound testing, I can’t imagine the DNR ever enforcing this since there is not a very repeatable and accurate method for checking sound level (I measured differently at every enduro I participated in!). There are just too many factors to consider when testing (distance from exhaust, position in relation to exhaust, RPM, 2 vs. 4 stroke, type of meter, calibration of meter, reflection of sound waves off surrounding area/structure, etc.). I could possibly see them prohibiting loud bikes from riding in an area such as Silver Lake but it would be nearly impossible to write tickets out on the trail unless the bike was obnoxiously loud. Every case where the bike was close to the 94db limit would end up in court!

 

[MWEISSEN]

Yeah, the early 90's was the last change in the law (my sister-in-law worked on this when she worked for the DNR).

I would agree that "close calls" on sound testing would be a nightmare for the DNR. I just don't think the juice would be worth the squeeze for them.

At some of the CCC rides, I've wondered about the guys doing the testing. One time the ridiculed my exhaust setup (there was nothing wrong with it) and proceeded to stuff the meter right in the pipe. Good thing it passed, because I would've given him some grief about that.

 

[Smit-Dog]

At the U.P. ride the guy checking SA, db levels, and ORV stickers held me back because he thought my ORV sticker was invalid. It was a different size and printed with a different font than he was used to seeing, but it was the '02 "rose" color. It said "ORV 02" right on it. Another guy at the check had to point out that it was in fact valid before I could go on.

 

[2TrakR]

Originally posted by BadgerMan
As far as the sound testing, I can’t imagine the DNR ever enforcing this since there is not a very repeatable and accurate method for checking sound level (I measured differently at every enduro I participated in!).

They (DNR) do enforce it. It's not a "fix it" ticket so I doubt you can truly fight it. Sorta like loud exhaust on your car - fix it AND pay the fine or scrap the vehicle (had my share of those tickets). Except they don't care if you fix it on the bike.
There is a strict guideline for sound checks - not everyone does it correctly/identically which is why people vary from check to check.
There is a certain RPM that needs to be reached, which is checked by vibration. This varies by the displacement of the bike (500s don't have to rev as high as 250s). That amount of vibration will vary depending on where they put the RPM/vibration meter, how hot the bike is, type of fuel (mixture), etc. Obviously lots of room for variation.
The decibel meter is supposed to be at a certain position and angle from the exhaust. 45 degrees at 12 inches sounds right, but I don't have the spec handy right now (nor do I do help much with sound check).
We've turned away quite a few (2 or 3 per event) riders at CCC events this year due to excessive sound. Also had people get irate 'cause that brand new FMF pipe failed the check and they KNOW it's not that loud (it is). We can't stop 'em from riding, just can't take their money for the event..
Personally.. quiet bikes are good (less sound = more ground).

 

[KTM Mike]

Originally posted by 2TrakR
quiet bikes are good (less sound = more ground).

Amen Brother on that one! Just curious - anyone know how a stock KTM 300 normally comes in on a sound check? Are they pushing the limit or are they well under?

No Offense to the 4 stroke crowd but man...some of them with after market pipes are truely excessive! they do sound "good" though :thumb: and to get the power it seems they all really need to be uncorked.

A real catch 22 - 4 stroke is "cleaner" so keeps the eco guys happy....but tend to be louder....so keep the eco guys AND joe average unhappy. Just cant win huh?

 

[MWEISSEN]

The KTM's 4 strokes are testament to the fact that companies can design a quiet pipe while making less noise. Yeah, there's more power with them uncorked, but they do pretty good in stock trim.

Since we're asking about different bikes, how about a KTM 250 EXC with the FMF Q silencer? Any sound check info?

 

[tripdog7]

I like Badgerman's rumor of legislation to make dirtbikes equal to snowmobiles in the eyes of the law. Could CCC, Blue Ribbon, or even DRN members lobby their local representative to introduce a bill to allow for this? Using revenue gained by local businesses due to the increased popularity of off-roaders... this isn't such a far flung idea. (of course, would environmental impacts, if any, be detrimental to such a bill?)