Stock exhaust can modification

try & pick up a second hand sx can. i think let it iddle for 15mins then off u go

Shouldnt be a drama mate just ride it. There is a good thread on here about modding the spark arrestor.

Many USA imported KTMs and I believe Bergs come with a screw-in diffuser on the end of the exhaust. This is not the spark arrestor, which is internal, but simply a noise suppressor. This diffuser can be removed with no problems.

I tried to get the end cap off my 2011 FE 570, and the thing is silicon-glued on tight. The Owner's Manual says on page 9 under Important Information, "The exhaust system on this vehicle has no owner serviceable parts," and they did their level best to prevent it. Ideas anyone?

All I could do is take the screen out of the tip, and replace the star bolt. I think it helped gas flow a little, and it didn't make the bike any louder.

Bergman suggested the use of a broomstick and a rubber mallet to break the silicon seal around the endcap of the factory exhaust can. Worked like a charm!

I did not remove as much tail pipe as he, and in fact I removed only about 1/8 inch. I figure I can remove more, and will do so in modest increments as judgment indicates, but can't remove less. I then rounded the blunt end of the tail pipe inside and outside to facilitate gas flow. Seems to have given the bike a little more pep and I can actually hear the exhaust with ear plugs and helmet on now. It's not loud by any means.

The inside of my right leg tells me there's a lot of heat buildup under the seat. I've now removed another 1/8 off the length of the small tail pipe inside the tail cap, for a total of 1/4 inch removed. Also drilled four holes around the small pipe to serve as a kind of bypass. That plus removing the inner layer of screen from the two-layer screen in the tip ought to help. I hope it isn't too loud. Time to take it for a test ride.

Results of test ride. It's not too loud at all, and the sensation of heat on the inside of the right thigh is noticeably reduced. Sound-wise it still sounds like it's not breathing right - sounds restricted. Next mod will be to drill four more holes around the perimeter of the small pipe where it is welded to the large one. Doing this one step at a time, although Brian011952 and others assure me that simply cutting off the small pipe altogether is the way to go and produces a mellow sound that isn't too loud.

One more iteration. I increased the number of 1/8 inch holes around the perimeter of the small tube in the tail pipe from 4 to 12. I don't have a photo, so I'll try to describe. This is on a 2011 FE570S.

If you look at the end of the factory exhaust can you see a round screen held in place by a multi-pointed star-shaped aluminum fastner. (If anybody makes a stainless steel replacement, I want to know about it.) You'd think that the inside diameter of the exhaust pipe would be the same as that of the round screen, and you'd be quite wrong. Inside the tail pipe, which is roughly an inch in diameter, you will find a smaller pipe which is roughly a half-inch in diameter. The two are joined together by what can only be described as a heavy steel washer. The outside of the washer is welded to the one-inch pipe, and the half-inch pipe is welded to the inside hole of the washer. The washer, then, forms a "step" that holds the two pipes together. It is through that washer that I've drilled twelve 1/8th in holes. As previously described, I've also shortened the half-inch pipe 1/4 inch so that the exhaust gasses flow through a less convoluted route.

The result is quite pleasing. It sounds like a big-bore thumper, but isn't too loud. If I was a racer I'd go with an aftermarket muffler, but I'm not and so don't have to spend $300. It's a good modification to the factory muffler, not as extreme as simply removing the half-inch pipe by cutting the larger pipe around the washer, and I believe (can't prove it) that it retains its spark arresting feature. This is probably all that I'm going to do to the factory exhaust can.

Went on a 4 hour ride this past weekend, and noted that at small throttle openings and downhill runs the exhaust note sounds like "chuff-chuff-chuff." Desipite the modifications I've made, I still don't think that the FE570S is breathing right. It performes well enough, it just doesn't sound right.

So I bit the bullet and ordered an FMF Factory 4.1 slip-on and the spark arrester from Bike Bandit. It's an expensive part and I hope it works as claimed.

In am also not happy with the standard mufler,rode about 700 km with my 2011 570,don't know if the european versions are the same as the U.S. models.cant get loos from the idea that the silencer is main reason that engine runs easily hot ( of course already removed the cat and perforated end cap ). For testing i arranged 2 damaged ktm silencers and extended the main alu outside by welding 2 pieces together for 8 cm extra length,now busy making straight inner perforated tube with bigger diameter with 3 welded conus shapes inside with 30 mm hole diameters,took the original piece pipe out of the end cap and making the inner tube fit between the front and end cap,fill it up with after market mufler material .have done this before to get better flow and performance with not much more noise.bought an acra header pipe but didn't like the acra silencer with the spark arrestor in it necesary to keep it in our noise regulations.ride the berg with 14/50 gearing

Concur. I had two initial negative impressions of the FE570S at point of purchase. One, the horn sounded like someone had stepped on a mouse. "Eeeeeeeeep." Terrible. I repaced the factory diaphagm horn with an automotive horn. Now it goes "honk." Two, the exhaust note. As delivered it sounded more like a sewing machine than anything powered by a 4-stroke single. I tried a series of modifications and made some genuine improvements (it no longer roasted my leg and sounded remotely like it was powered by an internal combustion engine), but it still just didn't sound right. I read that some had cut out the inner tailpipe altogether, but I thought that would defeat the spark arrester feature. So I drilled 12 holes in the "step" between the inner tailpipe and the outer tailpipe. That was better, but still not adequate. I am not willing to completely gut the factory muffler, so I replaced it.

Received FMF Factory 4.1 slip-on muffler for the FE570S this afternoon and installed it. Installation isn't even a 1 beer job - 15 minutes tops. The unit comes with a US Forest Service approved spark arrester, a rubber plug for washing the bike, all necessary mounting hardware, and adequate instructions.

You reuse the rubber gromets from the factory muffler as well as the aluminum washers for the outside of the mounting brackets, but you use much thicker aluminum spacers for the inside of the mounting brackets. They look too thick initially, but they work fine. Interestingly, the FMF muffler does not use the factory tension spring. They recommend using a high temp silicone seal for the joint between the muffler and the mid-pipe. I installed it dry and noted no leakage around the joint. I'll keep an eye on it.

The unit rides very close to the aft bodywork - within an eighth of an inch. I called FMF and they assured me that they test all of their products on the applicable machines, but shyed away from guaranteeing that the muffler wouldn't melt the bodywork. I considered some kind of reflective insulation to protect the bodywork, but I ran it up in the garage and the outside of the muffler remained astoundingly cool. Something else to keep my eye on.

Okay, you're jail bait if you run the bike with the muffler as delivered. It sounds good, but you'll get pegged for a hooligan by the first policeman you encounter. It's loud. It's obnoxiously loud. I think it's spend a night in jail loud, but that's just a guess. It actually sounds better with the spark arrester installed - a deeper exhaust note without the snap or crack of a nearly open pipe. It really sounds good, so much better than the factory muffler even with the series of modifications I made to it. The reason for the remarkable difference is the difference in the inside diameters of the two FMF tailpieces - 1 9/16 inch vs. 1 3/16 for the spark arrester. The spark arrester evidently provides a little back pressure - enough to make the muffler muffle. Clearly the machine breathes properly now. I haven't ridden it, just ran it in the garage, but I think that I now have the motorcycle that the Husaberg designers intended. The FMF muffler weighs on the order of two pounds less than the Husaberg unit. It might just be the best $300 I've spent since I bought the Husaberg.

I'm curious about the thicker inner spacers, any chance you snapped a picture of them compared to the stock spacer? I'm guessing this is so they can use the same can on a Berg or KTM. Leo Vince also show a bigger spacer for the Berg. What has me confused is I put a muffler from an 09 KTm 450xcw on my 10 fx450 and it bolted right on perfectly.

Stock spacers are no thicker than conventional washers. The replacement inner spacer provided by FMF with the muffler is roughly 1/2 inch thick. I'll snap a photo and post.

[attachment=0:nc8x3pq3]HPIM0109 (1024x763).jpg[/attachment:nc8x3pq3]UPSguy, here's the photo you requested.

Ruger said:

[attachment=0:148myty4]HPIM0109 (1024x763).jpg[/attachment:148myty4]UPSguy, here's the photo you requested.

Click to expand...

appreciate the picture, let me try asking my question a slightly different way. I'm just wondering why the bigger spacers are needed on the berg? The good folks at Leo Vince sent me a diagram of their canister for the bergs, same can as the KTM version again with a larger inside spacer for the front mount only for the Berg. The reason I am confused is that I took off the restrictive POS stock muffler and put on a KTM muffler from an 09 450xcw and it bolted on perfectly using the stock slim husaberg spacers.

SO, is the FMF muffler wider than the stock berg muffler? Just for curiousity sakes did you try mounting the FMF muffler using the stock spacers, what happened? Actually maybe I should go take mine off and remount it to see that it really did line up as perfectly as I think it does.

Guess what I am trying to figure out is if I can get away with a KTM version as I'd like one of the bling blue canisters?

I compared the width of the FMF F1 muffer and the Husaberg factory muffler with calipers, and the FMF unit is a tiny bit wider than the factory unit. Not enough to make an appreciable difference. The difference is where the brackets are posistioned on the two mufflers. FMF provides two identical spacers for the inside - just about a half-inch thick. Using them provides a zero-angle fit of the muffler to the midpipe. No leaks at the joint without using silicone. I did a trial fit using the much thinner factory spacers, and it looked to me that the rear tire might rub on the inside of the muffler.

I needed to warm the 'Berg up today to change the oil, so I took it for a couple lazy loops around the block. The first thing I noticed is that the machine starts easier with the new muffler. The second thing I noticed was the much deeper exhaust note. Even at idle you can immediately tell that the machine is breathing easier. The final thing I noticed was the throttle response while under way. It's a whole new machine. It'll straighten your arms if you're a little ham-handed with the throttle.