and while I'm logged on..just curious

Not much into customizing, but read an instructional article about how installing a straight or modified exhaust pipe could actually reduce 2 stroke engine performance. Apparently, the manufacturers design the OEM pipe to use "acoustical resonance" - that is sound waves in the pipe keep/push back gas in the cylinders longer for more complete combustion. Keeping in mind the use of exhaust power valves in certain engines, doesn't this actually make the aftermarket pipes less effective from a power point of view?

Figured you could put that higher learning to good use....
(get well soon)

From what I've learned so far in school that is all true, when dealing with a stock motor. When you get into modified heads, cylinders and carbs, that stock pipe will no longer be in tune with the flow any longer, then you need to go mod/aftermarket and start playing with flow dynamics to try and find that sweet spot.

What I can't understand is the OEM's spend millions in R&D, to get the acoustical resonance of the exhaust to allow for peak performance and engine longevity and reliability. Then people go out and spend big coin to just to save 5 to 8 lbs on a can, and lose 5 to 10 hp on their stock set up ................... I to am guilty of playing with exhaust mods thinking I can do better than OEM R&D boys



I'm sure there's a few on here that will disagree with me, but hey it's what I've come to learn so far

Thanks for the get well slomo, passed a few more stones last night (sorry to anyone I awoke in the northern hemisphere last night, with my cow moose like calls) my acoustical resonance seems to be well within speck for the time being

Nutter, stones have to be the most pain a man can go through, woman think having a kid hurts, I think its probably comparable!!

As for the can thing, ya for a stock motor you will lose due to Backpressure and such, it sounds cool (imo) but if you are doing it for performance, ther are way better routes to go. BUT, once you start doing carb and airbox mods, it can help.

I think of it like a body, no sense pushing more air out if you are still breathing in the same amount, and same as if you change your carbs or airbox and are bringing air in faster, there is no sense if you arnt pushing it out faster. It all has to be balanced.

P.S. I think I was pretty nuetral on this one dont you think?

Straight or modified pipe can do what ever you want! Including decreasing performance.
Manufacturers are driven mailny by one idea when producing sleds..max effect at cheapest price.
+ there are always compromizes to suit the "average" comsumer.
Sure there are many "fly-by-night" operations that will sell you junk makeing all kinds of perf claims usually ending up with inferior products doing little or nothing of what they claim other than increasing noise.
There are however gains (large or small) to be made in the performance of any engine by customizing parts & pieces including the exhaust to suit diff riders needs.
The greastest single example is the single pipe 90s Polaris & Yam SX triples. It's very cheap to produce a single exhaust pipe for those engines but the basic needs of a triple over a twin dictates you can't balance the harmonic scavenging properly. Claims of 20% power increase can be easily acheived with little to no decrease in fuel mileage or noise increase. Respected aftermarket manufacturers can make these aftermarket exhaust as quiet or very nearly as quiet as the stock exhaust. I personally can verify these performance claims!
My old 00 Yam Sxr600 @ 98hp stock would barely stay ahead of the new wave high performance 500s, now even with 20,000kms on it, it consistantly pulls away from my new 05 supposed top of the heap 600 @ 120hp & while it's now starting to get a little louder on the lake (needs new packing) you can drive it all day on the trail with virtually no-one knowing it's not perfectly stock.
We need to keep the noise down on our trails & there are lots of ways to do it, but the stupid stock exhaust law is simply to general & simply another ill concieved beauocratic bungle produced by those not in the know

Thanks for the courtesy of your replies! Interesting reading.

But remember...

Click to view attachment

I have an Aaen pipe with the stock can on my powertek. The pipe saved 6-7 lbs from stock. It will out pull a stock powertek but I have lost about 4-5 mph on top end. I got a good deal on it otherwise its not worth the money IMO. Its hard to beat the factory stuff nowadays unless your sinking big bucks into your sled.