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

[AgileMike]

LONG POST!! YOU HAVE BEEN WARNED!! THIS IS ALSO POSTED ON VITAL, BUT I THOUGHT A FEW PEOPLE MIGHT NOT READ VITAL

Caveats:
I was speaking with Mike Burkeen who works for the AMA. I’m sure his thoughts and opinions don’t necessarily reflect the AMA’s corporate stance. I am relaying the conversation I had this evening to the best of my ability. I did not record the call, but wrote down notes about an hour after the call ended.
Details:
I called the AMA earlier today to express my displeasure about not being able to race my Stark Varg in AMA sanctioned motocross. Mike Burkeen called me back about four hours later and we had a lengthy phone conversation. Mike is both friendly and very knowledgeable about the subject. Also, it’s easy to understand he truly loves motocross and genuinely cares about the sport. He is the father of motocross YouTuber Matt Burkeen, whose videos I enjoy very much.


Regarding E-bikes in general, the AMA has two major concerns which are: parity in competition and safety.

Mike acknowledged that the four stroke rules didn’t turn out the best, and the AMA really wants to avoid a repeat mistake with regard to electric bike rules. He said that peak HP is not the solution for parity, as electric bikes make more horsepower and torque at throttle opening. He also stated that electric powered machinery does not complete with ICE bikes in any other competition.


On the safety issue, the AMA sees two different problems with electric bikes. The first is that riders can not hear nearby riders, thus increasing the chance of cross jump, cutting off, etc other riders. This issue is hazardous to both other riders and the electric bike rider themselves. The second safety issue relates to leaving jump faces. With an ICE bike, it’s fairly easy to determine if the rider in front of you chops the throttle up a jump face. With a silent electric bike, this is much more difficult to judge, increasing the possibility of jumping on top of another rider. This issue is also dangerous for both riders.


Regarding Stark in particular, he relayed that Stark hasn’t been working hand in hand with the AMA. When the OEMs were working to create the electric 50s, they worked with the AMA for three years prior to the 50s release to ensure the AMA had time to create the correct classes and regulations. It seems like Stark hasn’t been doing this well. He also said they have been in talks with Starks frequently and communicated the safety issue regarding noise to Stark over eight months ago. Stark hasn’t responded with any solutions to the noise issue that he is aware of. He also stated that Stark hasn’t homologated the bikes yet. I forgot to ask if this was required for professional SMX only, or also applied to amateur racing.
WHAT I AGREE WITH:
1. Parity should be figured out. However, I feel that because electric dirt bikes can change power output with an app in a matter of seconds, it doesn’t have the same “can’t get it wrong” scenario as the 250cc and 450cc rules that were made for four strokes. Once the manufacturers invested millions of dollars in engineering and tooling, the AMA couldn’t just change it to 200cc and 380cc the next year. If the AMA decides that 50HP on electric bikes is parity for the 450 class, they can literally change it the next race with very little issues. All the Stark riders can simply set their maximum HP to 48 the next weekend.
2. Safety should be figured out. I feel that a Bluetooth or wired speaker could be connected to the Stark Varg phone and modulate decibel/pitch level depending on throttle position. I have a tech background and this problem is about 1/1000 the difficulty of designing and manufacturing the Stark.
WHAT I WANT STARK TO DO:
1. Have a working relationship with the AMA. I believe the United States is the largest market for dirt bikes in the world. It’s insane not to work together with the AMA for the good of everyone. I understand Stark was basically a start up for many years, but it’s time to grow up and invest time/money in relationships, especially the important ones.
2. Design a speaker for the bike!!!
WHAT I WANT THE AMA TO DO:
1. Please develop a working relationship with Stark, even if they haven’t been the easiest to work with. They were trying to create a brand-new electric bike in the depths of the Covid supply chain nightmare. Cut them a little slack for the good of all motorcycle riders.
WHAT I WISH ALL STARK OWNERS WOULD DO:
1. Put pressure on Stark to develop the speaker. Put pressure on Stark to work with the AMA.
2. Put pressure on the AMA to work with Stark.
WHAT I WISH ALL ICE DIRT BIKE OWNERS WOULD DO:
1. Realize that more options for people owning dirt bikes is a good thing. Nobody will make you buy/ride an electric dirt bike against your will.
2. Realize that no matter what you ride, we are all having fun riding our bikes, and we share that in common!!

 

[mbw479]

The biggest problem I have with the Stark is that it is so easy and fun to ride that I don't like riding my 250 2T or 350 4T anymore.

I am in Australia where Motorcycling Australia have allowed them to compete against ICE bikes, they have been going well in all divisions. However, I haven't seen a top-level Pro race one yet, that would be good to see. A Stark did win the 30+ QLD State title recently which was cool.

 

[Johnny Depp]

LONG POST!! YOU HAVE BEEN WARNED!! THIS IS ALSO POSTED ON VITAL, BUT I THOUGHT A FEW PEOPLE MIGHT NOT READ VITAL

Caveats:
I was speaking with Mike Burkeen who works for the AMA. I’m sure his thoughts and opinions don’t necessarily reflect the AMA’s corporate stance. I am relaying the conversation I had this evening to the best of my ability. I did not record the call, but wrote down notes about an hour after the call ended.
Details:
I called the AMA earlier today to express my displeasure about not being able to race my Stark Varg in AMA sanctioned motocross. Mike Burkeen called me back about four hours later and we had a lengthy phone conversation. Mike is both friendly and very knowledgeable about the subject. Also, it’s easy to understand he truly loves motocross and genuinely cares about the sport. He is the father of motocross YouTuber Matt Burkeen, whose videos I enjoy very much.


Regarding E-bikes in general, the AMA has two major concerns which are: parity in competition and safety.

Mike acknowledged that the four stroke rules didn’t turn out the best, and the AMA really wants to avoid a repeat mistake with regard to electric bike rules. He said that peak HP is not the solution for parity, as electric bikes make more horsepower and torque at throttle opening. He also stated that electric powered machinery does not complete with ICE bikes in any other competition.


On the safety issue, the AMA sees two different problems with electric bikes. The first is that riders can not hear nearby riders, thus increasing the chance of cross jump, cutting off, etc other riders. This issue is hazardous to both other riders and the electric bike rider themselves. The second safety issue relates to leaving jump faces. With an ICE bike, it’s fairly easy to determine if the rider in front of you chops the throttle up a jump face. With a silent electric bike, this is much more difficult to judge, increasing the possibility of jumping on top of another rider. This issue is also dangerous for both riders.


Regarding Stark in particular, he relayed that Stark hasn’t been working hand in hand with the AMA. When the OEMs were working to create the electric 50s, they worked with the AMA for three years prior to the 50s release to ensure the AMA had time to create the correct classes and regulations. It seems like Stark hasn’t been doing this well. He also said they have been in talks with Starks frequently and communicated the safety issue regarding noise to Stark over eight months ago. Stark hasn’t responded with any solutions to the noise issue that he is aware of. He also stated that Stark hasn’t homologated the bikes yet. I forgot to ask if this was required for professional SMX only, or also applied to amateur racing.
WHAT I AGREE WITH:
1. Parity should be figured out. However, I feel that because electric dirt bikes can change power output with an app in a matter of seconds, it doesn’t have the same “can’t get it wrong” scenario as the 250cc and 450cc rules that were made for four strokes. Once the manufacturers invested millions of dollars in engineering and tooling, the AMA couldn’t just change it to 200cc and 380cc the next year. If the AMA decides that 50HP on electric bikes is parity for the 450 class, they can literally change it the next race with very little issues. All the Stark riders can simply set their maximum HP to 48 the next weekend.
2. Safety should be figured out. I feel that a Bluetooth or wired speaker could be connected to the Stark Varg phone and modulate decibel/pitch level depending on throttle position. I have a tech background and this problem is about 1/1000 the difficulty of designing and manufacturing the Stark.
WHAT I WANT STARK TO DO:
1. Have a working relationship with the AMA. I believe the United States is the largest market for dirt bikes in the world. It’s insane not to work together with the AMA for the good of everyone. I understand Stark was basically a start up for many years, but it’s time to grow up and invest time/money in relationships, especially the important ones.
2. Design a speaker for the bike!!!
WHAT I WANT THE AMA TO DO:
1. Please develop a working relationship with Stark, even if they haven’t been the easiest to work with. They were trying to create a brand-new electric bike in the depths of the Covid supply chain nightmare. Cut them a little slack for the good of all motorcycle riders.
WHAT I WISH ALL STARK OWNERS WOULD DO:
1. Put pressure on Stark to develop the speaker. Put pressure on Stark to work with the AMA.
2. Put pressure on the AMA to work with Stark.
WHAT I WISH ALL ICE DIRT BIKE OWNERS WOULD DO:
1. Realize that more options for people owning dirt bikes is a good thing. Nobody will make you buy/ride an electric dirt bike against your will.
2. Realize that no matter what you ride, we are all having fun riding our bikes, and we share that in commo

I was talking about you over here:

AMA and Electric Motorcycles in AMA races

I don't even like bracket racing....head to head or forget it. that's the meaning of racing, to find out who and what is the fastest or most powerful. classes just muddy things up(except age brackets). 125's, 85's, 250's, 300's, 450's, 650's, electrics, let em all run together. find out what's...

electricdirtriders.com

 

[Fog 25]

Stark pay us our MONEY and we might let you race in AMA.
Just like all the Blue states pay us and we will let you sell bikes in our State.
All about the graft money and who pockets you fill up.

 

[AgileMike]

Stark pay us our MONEY and we might let you race in AMA.
Just like all the Blue states pay us and we will let you sell bikes in our State.
All about the graft money and who pockets you fill up.

To be honest, before I spoke with Mike Burkeen, I thought that he was a FUDster who just hated electric bikes and was making any excuse to ban them. I spoke with him for almost an hour, and I'm 99% sure that's not the case at all. I feel he has some legimate concerns regarding the noise/safety issue. I didn't include it in my initial post, but he and his son Matt both ride the Stark and really enjoy it. I also didn't get the feeling that the AMA was trying to shake down Stark for money. The tier 1 OEM membership is 15k annually. That's a drop in the bucket for Stark, who is selling 1k ish bikes per month at 12k per bike, or 12M monthly revenue.

In today's litigious society, the AMA doesn't want to get sued by some injured rider who blames the silent Stark for their injuries. I would encourage you the read the thread on Vital and "SlowOldGuy" is Mike Burkeen.

He really opened my eyes and changed my opinion of the AMA.

Instead of bashing the AMA, we need to pressure Stark to actually work with the AMA, especially regarding noise/safety issue.

 

[AgileMike]

I was talking about you over here:

AMA and Electric Motorcycles in AMA races

I don't even like bracket racing....head to head or forget it. that's the meaning of racing, to find out who and what is the fastest or most powerful. classes just muddy things up(except age brackets). 125's, 85's, 250's, 300's, 450's, 650's, electrics, let em all run together. find out what's...

electricdirtriders.com

I tried to read that thread but I can't understand where/what you were saying about me...

 

[hawk101]

I think Stark is ignoring the AMAs concerns because the bike has been allowed to race in Europe and Australia. They probably think if other countries don't have a problem with racing the Varg with gas bikes, then the AMA will eventually follow suit.

I'll bet the AMA holds firm for a while and only the major manufacturers creating electric competition and complying with the AMA safety concerns will force Starks hands.

Also, adding sound to Starks could be a Pandora's box that would catalyze public tracks requiring sound devices even on practice days. Stark probably wants to keep sound off the bikes unless really necessary, since adding sound might make the bike less appealing/attractive to consumers.

 

[Theo]

Another thing to consider is that the Stark is not as popular as I wish it was: at least here in northern Italy, where I also see a lot of riders from Germany, France, etc. at the track, after 25½ hours of riding I have never seen another Varg which was not a demo bike.
I don't know what happens overseas but I guess that if a significant amount of people used the Stark, then the AMA would be compelled to regulate its competition, while I'm afraid that most of the riders won't care about it not being allowed.
I think that the root problem is that people just go with the flow and don't want to admit that the Stark is, I think, a better choice for many riders. I always feel like that guy when I go to the track; this doesn't stop me and I always have fun and go home happy, but feeling a weirdo while I've probably done the best choice is pretty frustrating. So many people have said stupid things like do you need to be gay to buy an electric MX bike or do yo become gay afterwards; now even if they try a Stark and they like it how can they admit that?
I hope that kids who grow up riding electric mini bikes will notice how annoying it is to keep a 125 in the right gear and start complaining about the fact that they are not allowed to use bigger electric bikes.
I'm convinced that the problem is that the crowds don't think, they follow trends.

 

[Fukenfast]

Full closure before I post the question, I have never raced MX/SX but have raced hare scrambles, super bikes and raced a KTM450 in SM trim before switching to the stark. Is the sound factor a major issue/safety concern? Maybe its my deaf ass but, the FMF on my SM was so loud I couldn't hear anyone on another ICE bike behind me unless they yelled, which is how I knew I was being passed in hare scrambles as well.

@Theo there's at least 6850 worldwide, as my buddy just got 6849. I agree that popularity will continue to grow with the younger generation learning on e-bikes and how easy they are to ride...it just ups the enjoyment factor for me. I also have a left wrist issue from years past and the lack of clutch manipulation makes life so much better on the bike.

 

[Satellite]

Humm... how loud is your cell phone? While I agree I would like the Stark phone to make noise its not for racing safety its for pit safety. How many times do people fidget with the throttle? You would be surprised! Just standing there chatting someone will twist the throttle not thinking the bike is live. With a gas bike not a problem you can hear it running and know. My electric bike has been launched multiple times and electric has full torque at zero rpm. I wrapped my Surron around my porch support beam because I got distracted by the dog and forgot the bike was live. Even my Beta with Rekluse Clutch will catch people off guard while running if they fidget with the throttle while in gear running. But while riding the Stark in a Race I doubt the Stark Cell Phone will be loud enough on its own to satisfy the safety concerns, especially if competing with 4-Strokes those things are noise generators!

 

[hightechnature]

I finely got my Stark Varg in July 2024. I asked the ECHO dealer how many they were selling. He said a "ton of them". I asked how many units from the first sale until my July purchase, and he said he did not know. I asked him if total deliveries were around 1000 units and his answer was "No way 1000 -much less". Respectfully, there is no way that Stark is selling 1000/month as AgileMike suggests. Remember that Alta sold approximately 950 units in total in 3-4 years of production and it had largely the same performance (I own both brands).

If we want to know the volume sold per month, let's all start a thread with our serial numbers and delivery date. I suspect a success would be 1000 units sold worldwide in the first 12 months of production.

The key point is that Stark is smart in focusing 100% of their talent on building a great unit and letting the AMA figure out how to deal with their technology later.

 

[Theo]

If we want to know the volume sold per month, let's all start a thread with our serial numbers and delivery date.

There is already one:
Varg production numbers / VIN

 

[Johnny Depp]

LONG POST!! YOU HAVE BEEN WARNED!! THIS IS ALSO POSTED ON VITAL, BUT I THOUGHT A FEW PEOPLE MIGHT NOT READ VITAL

Caveats:
I was speaking with Mike Burkeen who works for the AMA. I’m sure his thoughts and opinions don’t necessarily reflect the AMA’s corporate stance. I am relaying the conversation I had this evening to the best of my ability. I did not record the call, but wrote down notes about an hour after the call ended.
Details:
I called the AMA earlier today to express my displeasure about not being able to race my Stark Varg in AMA sanctioned motocross. Mike Burkeen called me back about four hours later and we had a lengthy phone conversation. Mike is both friendly and very knowledgeable about the subject. Also, it’s easy to understand he truly loves motocross and genuinely cares about the sport. He is the father of motocross YouTuber Matt Burkeen, whose videos I enjoy very much.


Regarding E-bikes in general, the AMA has two major concerns which are: parity in competition and safety.

Mike acknowledged that the four stroke rules didn’t turn out the best, and the AMA really wants to avoid a repeat mistake with regard to electric bike rules. He said that peak HP is not the solution for parity, as electric bikes make more horsepower and torque at throttle opening. He also stated that electric powered machinery does not complete with ICE bikes in any other competition.


On the safety issue, the AMA sees two different problems with electric bikes. The first is that riders can not hear nearby riders, thus increasing the chance of cross jump, cutting off, etc other riders. This issue is hazardous to both other riders and the electric bike rider themselves. The second safety issue relates to leaving jump faces. With an ICE bike, it’s fairly easy to determine if the rider in front of you chops the throttle up a jump face. With a silent electric bike, this is much more difficult to judge, increasing the possibility of jumping on top of another rider. This issue is also dangerous for both riders.


Regarding Stark in particular, he relayed that Stark hasn’t been working hand in hand with the AMA. When the OEMs were working to create the electric 50s, they worked with the AMA for three years prior to the 50s release to ensure the AMA had time to create the correct classes and regulations. It seems like Stark hasn’t been doing this well. He also said they have been in talks with Starks frequently and communicated the safety issue regarding noise to Stark over eight months ago. Stark hasn’t responded with any solutions to the noise issue that he is aware of. He also stated that Stark hasn’t homologated the bikes yet. I forgot to ask if this was required for professional SMX only, or also applied to amateur racing.
WHAT I AGREE WITH:
1. Parity should be figured out. However, I feel that because electric dirt bikes can change power output with an app in a matter of seconds, it doesn’t have the same “can’t get it wrong” scenario as the 250cc and 450cc rules that were made for four strokes. Once the manufacturers invested millions of dollars in engineering and tooling, the AMA couldn’t just change it to 200cc and 380cc the next year. If the AMA decides that 50HP on electric bikes is parity for the 450 class, they can literally change it the next race with very little issues. All the Stark riders can simply set their maximum HP to 48 the next weekend.
2. Safety should be figured out. I feel that a Bluetooth or wired speaker could be connected to the Stark Varg phone and modulate decibel/pitch level depending on throttle position. I have a tech background and this problem is about 1/1000 the difficulty of designing and manufacturing the Stark.
WHAT I WANT STARK TO DO:
1. Have a working relationship with the AMA. I believe the United States is the largest market for dirt bikes in the world. It’s insane not to work together with the AMA for the good of everyone. I understand Stark was basically a start up for many years, but it’s time to grow up and invest time/money in relationships, especially the important ones.
2. Design a speaker for the bike!!!
WHAT I WANT THE AMA TO DO:
1. Please develop a working relationship with Stark, even if they haven’t been the easiest to work with. They were trying to create a brand-new electric bike in the depths of the Covid supply chain nightmare. Cut them a little slack for the good of all motorcycle riders.
WHAT I WISH ALL STARK OWNERS WOULD DO:
1. Put pressure on Stark to develop the speaker. Put pressure on Stark to work with the AMA.
2. Put pressure on the AMA to work with Stark.
WHAT I WISH ALL ICE DIRT BIKE OWNERS WOULD DO:
1. Realize that more options for people owning dirt bikes is a good thing. Nobody will make you buy/ride an electric dirt bike against your will.
2. Realize that no matter what you ride, we are all having fun riding our bikes, and we share that in common!!

Parity is not expected in age classes. 2t’s are also not raced in other sports.
Safety is not a given in motocross, and only a fool would run up a electric bikes ass because they checked up on a jump.
When Honda releases their bike, all will be forgotten. Sorry, but Mike is a tool .

 

[Chaconne]

One of the key selling features of the Stark is noise reduction. Engine noise complaints by track neighbors have at least been partly to blame for pressure to close tracks in the US at least. And 4Ts have not really been quieter than 2Ts. Plus, engine sound is not always a good safety indicator given helmets, your own bikes noise level (current Yamaha yz450fs will drowned out other bikes sound anyway) and other distortions.

Proximity is usually what sound can be used for at least for track racing. Maybe outfit the bikes with proximity sensors with indicators on the bars. Could have them on both ICE and E bikes if safety is really an issue. At least for racing that would be better than relying on engine noise. And once again we can chase tech that has been available in cars for over 15 years.

 

[Erwin P]

I have a Stark and a 300 2 stroke Enduro. When i ride that there is not a single 450 MX rider that can hear me comming up.
I have an easier time to hear a Stark comming up on my 300 than i do hearing a 2 stroke comming up when i ride a 4 stroke.
To make the kind of noise to overcome a 450 you would need a speaker the size of the rear rim, where are you going to put that...

I really like engine noise, i'm a motorhead through and through, but as loud as 450's are is kind of sickening since it's hard to even think when a couple of them are racing around.

I frequent a track where there is a big noise complaint. When we removed all the 2 strokes from the track the measurement hardly changed, when we removed the 4 strokes we fell well under the very low licence we have, hell even the neighbor filling official complains for years said he could live with that.

Maybe we should go to the root of the problem, the 4 strokes that are insanely loud. Outright ban the things or make regulations that add effective silincers like we allready see in enduro and are at least half as loud.
There is not a proper reason to not allow 2 strokes with Enduro dampers and Starks on 1 track, the can hear eachother well enough.

 

[Johnny Depp]

One of the key selling features of the Stark is noise reduction. Engine noise complaints by track neighbors have at least been partly to blame for pressure to close tracks in the US at least. And 4Ts have not really been quieter than 2Ts. Plus, engine sound is not always a good safety indicator given helmets, your own bikes noise level (current Yamaha yz450fs will drowned out other bikes sound anyway) and other distortions.

Proximity is usually what sound can be used for at least for track racing. Maybe outfit the bikes with proximity sensors with indicators on the bars. Could have them on both ICE and E bikes if safety is really an issue. At least for racing that would be better than relying on engine noise. And once again we can chase tech that has been available in cars for over 15 years.

Using noise as a safety excuse is just BS. The bikes have been racing together for 2 years now all over the world without a problem. Noisemakers could solve it, but they will find another excuse, probably a brake light for off throttle I'm not humoring them anymore, just calling them out as liars.
They have locked e bikes out mainly due to AMA and it's insurance, yet the insurance companies don't have a problem with e-bikes, just the promoter group. Clowns.

 

[Johnny Depp]

I have a Stark and a 300 2 stroke Enduro. When i ride that there is not a single 450 MX rider that can hear me comming up.
I have an easier time to hear a Stark comming up on my 300 than i do hearing a 2 stroke comming up when i ride a 4 stroke.
To make the kind of noise to overcome a 450 you would need a speaker the size of the rear rim, where are you going to put that...

I really like engine noise, i'm a motorhead through and through, but as loud as 450's are is kind of sickening since it's hard to even think when a couple of them are racing around.

I frequent a track where there is a big noise complaint. When we removed all the 2 strokes from the track the measurement hardly changed, when we removed the 4 strokes we fell well under the very low licence we have, hell even the neighbor filling official complains for years said he could live with that.

Maybe we should go to the root of the problem, the 4 strokes that are insanely loud. Outright ban the things or make regulations that add effective silincers like we allready see in enduro and are at least half as loud.
There is not a proper reason to not allow 2 strokes with Enduro dampers and Starks on 1 track, the can hear eachother well enough.

This is it. Nothing makes sense. There's no science being used. It's just OEM control of the sport, protecting their business interests. Safety is just an excuse, as is noise.
TOO QUIET!

 

[Erwin P]

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.

 

[Theo]

I have a Stark and a 300 2 stroke Enduro. When i ride that there is not a single 450 MX rider that can hear me comming up.
I have an easier time to hear a Stark comming up on my 300 than i do hearing a 2 stroke comming up when i ride a 4 stroke.

I frequent a track where there is a big noise complaint. When we removed all the 2 strokes from the track the measurement hardly changed, when we removed the 4 strokes we fell well under the very low licence we have, hell even the neighbor filling official complains for years said he could live with that.

And 4Ts have not really been quieter than 2Ts.

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.

 

[Johnny Depp]

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’ve always believed that it’s on the overtaking rider to get by safely. Hollering is easy.
Bringing all noise down makes the most sense, unfortunately it’s like pushing a rope.