RE: Stark - My conversation with Mike Burkeen, AMA Deputy Director of Racing

Erwin P

Well-known member
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Netherlands
There are a couple of scientific reasons for which 4 strokes are expected to be louder than 2 strokes and bother people more:
• the highger the engine displacement, the louder its sound and 4 strokes usually have higher displacement,
• the lower the frequency, the farther the sound wave can travel, since a longer sound wave (wavelenght and frequency are inversely related) will go through and around objects better; this principle is used even with those disinctive horns used on large ships. 4 strokes have less frequent ignitions and their sound is more low pitched, compared to 2 strokes.
Main reason is way higher compression and thus louder bangs per ignition.
 

Chaconne

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191
Location
Massachusetts
I have to agree a little bit on the noise though. While training with slow riders (i'm slow, but even i pass people) you have to be really carefull because they don't notice you comming up. I have that less on my 2 stroke. The 4 strokes really don't hear you although the guys riding enduro bikes should be able to. But the 2 strokes (especially enduro's) can hear you. However their brains don't connect the Stark noise with an incomming bike yet. Can't blame them either. I hear it al the time so i immidetly hear and recognize a bike incomming, but their brain is not trained at it yet. I think that will improve over time, but for now Starks are still an odity.

But last year i was mostly the only one at a track with +- 100 people, this year i'm seldom alone and plenty of times there are around 5 Starks. An with that you start to see more people notice you when you come up from behind.

I think, speaking for the Netherlands, 2 and 4 stroke noise have to come down. So many complains and restrains on MX tracks. And a very decent workable solution is there. Enduro mufflers are way quiter. If the Importers of all OEM's stick their head together and at least sell the bikes new with an Enduro muffler they all have the same loss of power. And to be honest, most people can really do without the last 3HP.
Also tracks can come up with it being mandatory. Our small local track is considering this. Offcourse people are complaining about it being expensive. But somehow those show up with new bikes every other year that go to the suspension tuner before riding their first meter.

And well, if everybody drops about 3-5 dB, the ''Safety issue'' is more or less gone as well.
I think it will be harder to reduce 4T noise even with enduro exhaust. I used some of the FMF noise reducing exhausts on my previous 4Ts and I don't think a few db will make a difference to a lot of the complainers especially if there are many bikes. The new yz450f is loud on intake and exhaust.

And with 2Ts even with reduced sound it wasn't just volume, the annoyance of many buzzing chainsaws was just as much of an issue as the actual volume at least in my experience with neighbor's noise complaints.

Better range is all it will take for E-motorcycles to take over I think. Having cyclically timed explosions with petrochemicals mostly can't be made quiet or clean with the current tech at least. I know and respect folk's love of ICE and the associated sound but not everybody likes it. Maybe when tracks were far away from homes it was somewhat more tolerable. At least here in the US folks plop down $1,000,000+ for a McMansion out in the sticks and expect yuppie solitude and are intolerant of a pack of chainsaws...
 
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