So I have been playing around with the different power tips available for the Two Brothers M5 cans in an attempt to see what sounds they make. I found the smaller P1 tips don't make much difference in sound, but do add some bling to the back. The longer P1X tips do make a noticeable difference, but are still quite loud. Looking at the P1 tips made me think of adding some additional restriction to see what it would do. I used JB Weld to attach a 5/8ths washer to the back of each P1 tip. I tried different epoxies but so far only the JB Weld has held. The addition of the washers has made a drastic reduction in sound (only slightly louder than stock), with no noticeable change to performance, although I have not had it dynoed this way. I still hit the same top speed on my super secret test track, and it revs and wheelies as easy as ever. While it is very quiet at idle, and low RPM, the motors character is still quite obvious, and sounds very mean at higher revs. So this is a very easy and cheap solution for the folks with M5 cans they think are too loud. It also did away with the deceleration pops of the open cans.

 

Clever. Thanks for posting that. I am trying to figure an inexpensive experiment to quiet my Jardine RT -1s. I don 't want to spend almost $100 for the Jardine tips I might not like.

Now I just need washers ... 2-1/4" in diameter.....!!

 

That's pretty crafty. I have the P1 tips on and am happy with the sound. But I'll keep your idea in mind if I feel the need to be more considerate of my neighbors.

 

Cranken, look at http://www.boltdepot.com/Product-Det...x?product=3068
They aren't the largest either.

Tomb, that was my thought. I now have no qualms firing it up in the morning and warming up a bit before leaving. It also allows me to bomb around more, flying under the audible radar if you will.

 

Now if we could just find a way to adjust it on the fly.

 

The nice thing about the Two Brothers tips, they can be changed or removed in a minute. I take mine out for Friday night shenanigans.

 

I could see someone using two different mufflers. Identical on the outside, different on the inside. A quiet one on the left and a LOUD one on the right, or vise versa. You could use an electric cutout to switch between the two mufflers.
A normal switch mounted on the dash could be used to switch between the two. Or, a RPM activated circuit to turn on the cutout. Get 'er up to 5,000 RPM's and BRAAAP!

Someone do it.

 

Some pictures of the appearance when installed.





Sounds quiet, looks awesome. (Didn't have them in for this pic)

 

Maybe some sort of a mechanical aperture device, connected to the tip. It would be adjustable by turning the tip. Then we could develop a motorized tip, and tie it to a throttle position sensor.

 

Very interesting, I wonder what can you do on the older style Two brothers... Anyone tried? I'm assuming you can fit one from another manufacturer as long as it is the same diameter and the bolt to connect.

 

I'm thinking a mechanical aperture tied to a dial potentiometer so you can literally dial in the desired volume depending on the circumstances.

 

Or you can do a sort of actuator that works with the amount of throttle turn/RPM like the CBR1000RR have in the stock muffler.

 

Or even better, take it to a whole new level with some afterburners the vtr will become a rocket ship

 

Yeah, looks like this is not a new idea for the exhaust near the engine. Yamaha had an exhaust valve on the RZ, the YPVS. Didn't know they had them on the CBR1000RR though.

 

So I finally got a chance to do a top speed test at my super secret off-road testing grounds, with both the washer baffles in place, and while I do really like the sound, there is an HP penalty (expected). Looks like I lost about 5mph (per the GPS) from my usual 145mph actual top speed (speedo reads 157ish), which is a little lower than the magazine claimed 148. With a previous dyno reading of ~102hp to the rear wheel, I'm guessing that equates to ~10hp lost when corked up and quiet.