Why aren't 4 Stroke Silencers shorter?

I chopped 4 inches , doesn't seem to have made any difference in performance, but definitely looks better.  It also doesn't seem to be any louder.

Shorter muffler = les top end !

Stock RMZ 450, didn't have any top end anyway.  But again, I haven't noticed a seat of the pants difference.

I’d bet that Tomac’s outdoor silencer is longer that what Star runs on his SX YZ450F.

I think a big factor is side plates getting smaller and showing more muffler, my 2022 yz250fx has the muffler almost completely tucked behind the plate. My buddies 24 yz250f has my FMF 4.1 off my 22 for a race and it looks way longer on his bike than it does on mine. 

Kawasakis with the stock exhaust don’t even look like they have number plates on the bike… those things are like bazookas. 

They are going to get longer next year with the sound checks tightening up the reins 

I cut mine down.   no noticeable change other than I no longer hit my boot on it when swinging a leg over.

They do not have to be long.  Yamaha had a mechanical silencer on the 2008/2009 450f.  I had both years, no issues.  They were very small compared to what we have now.  

Sell more titanium and increase the odds of destroying it.

Planned obsolescence.

Since it's such a simple task and they should have figured it out by now, why not build your own and start cashing in on the market?

25 years ago, I did the math and had some custom reverse cone megaphone pipes made by Air Cone in Nevada for XR250 and 400. They did make more power, but it was minimal and were loud. I reduced the core size and put a turn down cone on the cap to reduce noise. Cool as they were, four strokes are NOT two strokes and the exhaust has minimal effect besides weight and looks, and noise.

Why is Andrew Short not short?  Some things just be the way they be.

The 2008–2009 YZ450F silencer was pretty short.

https://motocrossactionmag.com/ask-the-mxperts-the-secrets-of-the-2008-yz450f-muffler/

That applies to two strokes, but not so much 4 strokes.    A shorter muffler tends to take away bottom end on a 4 stroke.   Thats why you see some outrageously long header pipes in supercross.   It makes the overall length of the exhaust system longer, and gives better bottom end.   But there is a lot more in play for tuning a 4 stroke powerband than just the total length.

I think that's the one often referred to as the "ice cream cone" muffler and was widely criticized as detuning the motor and having poor throttle response.

Guys are dropping a grand on aftermarket silencers to replace stock ones that performed better than the 08-09 YZF can - they'd probably be willing to drop 2 grand to get rid of one of those.

That's actually a good question.

That KX450 bazooka is crazy. You just think "Do they not see that huge pipe sticking out the back of it?"

Lol

Id contribute a lot of it to tuning, also heat. The longer the exhaust and silencer the more heat it can absorb, the shorter? You see where I'm getting at here. 

Running short exhaust on 90% of 4 cycle engines is not a very good thing. The exhaust will build up heat very quickly. 

Do you believe the laws of physics have changed in the last 20 years?

Kawasaki got criticized bad for years for loud mufflers.  So they listened to the magazines, made it quieter by being longer, and then got criticized for it being long.  

Oh wow....you showed him.

Feel better now?

I think you are confused. The Kawasaki Bazooka has a self-transport device attached to it that looks a lot like a motocross motorcycle. You can ride it in exactly the same way. 

There is real money in aftermarket stuff- maybe the OEM do not bother with spending $ on new tech because it's a remove and replace item for most.  They do what it takes to meet minimum requirements and let it go there.  

I've had a few aftermarket pipes over the years, slip on and complete systems, I don't know, they were cool and all but it's a bullshit waste of $600-$1000.00 IMO.

"side plates getting smaller and showing more muffler,"

LOL.  Sounds like a euphemism for girls in bikinis.

^I am totally pro- girls showing more muffler. 

So many babies riding motocross today, complaining about how long a muffler sticks out past a tiny side plate, more worried about looks than performance and then waving off people when they tell you that shorter 4-stroke exhausts hurt performance (and make more noise) lmao

I have some pink tassles for your handlebars if you want

The reason that mufflers aren't shorter is the same reason that modern suppressors (largely, K can sizes aside) haven't gotten shorter.  It turns out, it's hard to beat physics and that generally longer=quieter. 

DB Regulations will probably make them longer in the future.