Posts
35
Joined
10/23/2025
Location
Essex, ON
CA
Hey all, ive got a 2020 ktm 150sx and am looking at some aftermarket silencers, mostly because of the sound and looks but I am curious about the performance. Between the r304 and the 304, is there a major difference between the 2 and compared to stock in terms of power band, peak horsepower, ect? Also is there a difference in sound between the 2 as well as compared with stock? Which one would you recomend for the 150sx as well. Wondering if anyone has dyno data as well to see the effects on power at high and low rpm. I dont want it to make the bike any worse.
Never used the 304, but I have an R304 on my 2016 125 and 150. Very raspy exhaust tone, maybe a smidge of bottom end, and looks a million times better than what came on it stock. I’m pretty familiar with these bikes and can’t say I’ve ever seen anyone run the standard length 304.
Did you notice a sacrifice on the top end at all? Also do you recomend it haha.
No, but I also had PC do just about everything they could to the engine as well, so it’s not comparable to bolting the silencer onto a stock bike.
I will say that was almost ten years ago, and the weld for the bracket failed on mine about a year ago. I emailed PC asking if I could buy the bracket to tig back on, but they went ahead and sent me a brand new complete silencer if I paid $25 or so in shipping. For that reason alone I will always buy PC stuff or recommend it when I can.
I have used the short PC silencer and the stock one on a 2021 150sx. It does what it does on the 125 and gives a sharper hit from bottom to mid but then it runs out on top sooner. Whether that is because it makes more power and runs out of RPM faster or whether it just lacks top end pull I cannot say. I preferred the stock silencer because it was smoother. If you want to try the shorty I will give you a deal on a good used one.
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Was the rpm difference very noticeable? Also I live in canada, would you be able to ship here if you can cut me a deal?
I don’t know if the stock silencer pulled any further or if the shorty got to the limit faster. They sound different so it is hard to tell. I think I have shipped to Canada before. Pm me your address and I will look. Shipping to Canada might not be worth it since these silencers are not that expensive new.
Same here, I don't prefer the shorty mufflers on the 125/150 because of the loss of overrev. The extra bottom snap can be useful on tight tracks, but the quick run out and extra shifting can be annoying on faster tracks. Regardless of which muffler you choose, play with the PV adjuster to tailor the powerband.
Ah I see, so if I choose a shorty, would I be able to compensate with it by using the powervalve screw?
To some extent. You won't completely change the character but can shape the hit and powerband a little.
What do you recomend as the powervalve setting. Also im leaning towards the shorty as in my area we dont have large tracks persay and I mostly ride in the woods as well on some trails and small tracks.
I think on my 150 I am 2-1/4 turns in from all the way out. But there is no one correct answer as each bike runs a little different. Start there and don't be afraid to play around with it. Try different settings and see what suits you.
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