[250 Tom]

I would not buy either one. Wait until someone comes out with a quieter solution. I may also go back to the stock exhaust. Its an expensive mistake. Oh well

 

[bungie4]

As much as I hated to do it, I put the stock exhaust back on. I loved the way the bike looked but the sound was way to loud.

Hehe.. were flip floppin. I've got my 2Bros back on the bike. Don't sell it just yet. I'm going to be trying out Plan C before the end of the weekend and I can pretty much guarantee I can cut the sound level by at least 25%. Don't know how much it will kill performance though.

Lets face it, the 2hp gain on the top end won't be noticed unless your racing. But anytime you introduce any sort of obstruction to kill the sound your going to introduce back pressure. But I like the idea of the weight loss and the looks.

 

[sendler]

Car Muffler?

Might be a long wait for a quiet slip on. All of the after market mufflers a basically the same. A straight through hole surrounded by stuffing. They work fine on everything but single piston bikes which are apparently louder than anything else. How about a car muffler? It would look crazy but might perform well. Starting to get heavy again though at 11 pounds.
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[Brian]

I like the idea of the old style supertrapp tuneable mufflers. They were made originally for single cylinder dirt bikes. You could tune the sound/backpressure.

 

[mxracer56]

I am really sorry to hear that the px1 didn't do anything. I was hoping that it would make a difference.

 

[Aufitt]

I like the idea of the old style supertrapp tuneable mufflers. They were made originally for single cylinder dirt bikes. You could tune the sound/backpressure.

Yeah I was hoping FMF would do that type like their dirtbike ones, I still have a TTR 250 fmf muffler I would like to adapt.. but its too scratched up.

Experimenting with that bike it always made best power across the range when it was just muffling it to an acceptable level to pass our enduro club noise db testing to make it legal to race the state titles.

 

[250 Tom]

Have an idea. I have the yosh slip on. The silencer is nothing but a solid metel pipe that reduces the size of the outlet. Would it be possible to turn it into a baffle. Thinking about pulling it out drilling some fairley large holes up and down the pipe and then wraping some packing around the pipe and putting it back in. Would have to also wrap it with wire or something to keep it in place. whats your thoughts on this? I really dont know much about working on bikes but its the only thing I could come up with to try and quiet this thing down.

 

[Aufitt]

When I get my yoshi I'm going to make a baffle insert similar to a Pro circuit one and repack the muffler with stainless steel pot scrubber wool at the right density.. works on dirtbikes.

I like the Yoshi as its the only triangular muffler I know of.. looks right on a cbr.

 

[250 Tom]

When I get my yoshi I'm going to make a baffle insert similar to a Pro circuit one and repack the muffler with stainless steel pot scrubber wool at the right density.. works on dirtbikes.

I like the Yoshi as its the only triangular muffler I know of.. looks right on a cbr.

Yes I agree they look great and light compared to the stock muffler

 

[bungie4]

I am really sorry to hear that the px1 didn't do anything. I was hoping that it would make a difference.

There was a bit of difference at idle and I mean a bit. Above that. No diff.

I'm gonna mod the original tip and try to recoup my $ I paid for the P1X tip. Hey, it looks trick!

 

[bungie4]

Shutting up the 2 bros!

Okay, here's plan C.

I finally got over to Home Depot and picked up two Moen part # M2180. Which in laymans terms are 1.5" bar sink strainers, chrome. Hey, nothing but the blingiest bling for my CBR!

Anyway, the idea is to put in the inlet side of the factory 2 Bros tip.

I'm not doing it tonight, but I did do a trial fit.

This will have to be tapped in the rest of the way with a socket and a hammer. Otherwise its a perfect tight press fit. I can't see it ever coming out by itself, but if it works, I'll run two rivets through it.

You can see the amount of surface area in this pic. I'm sure this will pose a significant restriction. It should really do a good job shutting it up! If it seems like to much restriction this would be _easy_ to open up a few of the holes with a drill.

Total cost: $2.99 and it'll be completely invisible.

I'll make a sound clip tomorrow. Promise.

 

[sendler]

outside

I would probably just stick it in the outside first so you can start drilling it little by little without dismantling anything until you get it where you want, and then put it on the inside to hide it.

 

[sendler]

weighted flap

I was at Honda today and noticed that the CBR1000RR exhaust has an actual flap blocking off most of the outlet tip with a spring or servo to open it only when needed for high flow. That would be a nice solution for all of these slip ons that are turning out to be too loud. Highly restricted at idle to putt quietly out of the neighborhood, and wide open under high load for the best performance under full throttle. I have also seen dynos that show the stock RR muffler to be within 2% HP of the best slip on.

 

[llory]

Hope plan C works out for you!

 

[Aufitt]

If that works Bungie.. look at restricting the inlet side of the muffler.

You wont lose power.. gain if anything.

Once I fit my yoshi I will hack open the worthless stock muffler for a look.. has anyone done that yet?

 

[bungie4]

Update:

Success!

Video/Sound clip is uploading. With my internet connection, recently downgraded to the 'Lite' (read: SLOW) connection, should be done in about 3hrs.

Tapped the piece in home. Really tight fit. I don't see any need to rivet it in. Fired it up. How to quantify this... Lets call it about 25% of the volume between the stock pipe and the 2Bros. But I was worried about restriction. Hey lets face it, the diff between the stock pipe and the 2Bros is only 2 hp. The stock unit must flow pretty good.

So I opened up the center hole with a step bit to about 9/16ths. Ah ya, thats the ticket. About 50% between the stock and the 2 Bros.

Still has a little bark when you get on it a bit.

PERFECT.

So there you have it. Barring any sort of fueling problems (can't see that happening), it looks like this is the solution, or, at least, one of the solutions!

 

[bungie4]

CBR250RA :: MVI_0607.mp4 video by Bungie41 - Photobucket

Sound clip. You can hear a crow cawing at the start to give you an idea of the sound levels. This was a cold start and it's a tad louder than when warm.

Went for a ride while this was uploading, no diff in power, just a HUGE diff in the sound level.

So all you guys with loud 2Bros. This seems to be the best solution. Hit up Home Depot or Lowes or wherever, spend $3 and about 15 minutes of time to shut it up!

 

[motorradmike]

Steve, it looks (sounds) like you've done it! I'm going to try the same mod on my Yoshi "low volume" insert. I haven't measured the diameter of it though. How long is the 2Bros insert? The chrome plated steel should hold up. I too don't think there should be any fueling problems. You're a genius...thanks for passing on your solution!

Mike

 

[bungie4]

How long is the 2Bros insert?

The inside portion of the insert is about 4" long. the P1X insert is only about 2" long but it's of smaller diameter. I modded the stock insert.

Exterior dimension of the interior part of the pipe is 1 1/2, inside is about 1 3/8. The little strainer is tapered from just under 1 3/8 to 1 1/2. Hence my comment about tapping it home.

You can buy these strainers in different diameters so just measure you pipe first. Theirs even a little lip on the 'large end' of the strainer to keep you from driving it in to far.

****, I should put these things up on EBay and sell them for $15 a shot!

 

[motorradmike]

I measured my Yoshi insert and it is 1 1/2" swagged down to 1 1/4" about 1 3/4" down at the inlet end. So I will cut off at 1 1/2" transition. The length remaining will be about 4", very close to yours. Heading to Home Depot for the strainer and a step drill now! Thanks again, Steve. I, and a few others owe you, dude! Sell a kit (strainer and instructions) on this website or eBay for $19.99. Might pay for your 2Bros!

Mike