CodeMonkey

I have been told that the 'catalyst' part is not in the USA exhaust systems.

Beyond that, the end piece (with all the holes in it), I have gone to some trouble to make sure it stays in. I want it to serve as a spark arrestor. I know it isn't certified, but from the design it looks like it would do the job. If it comes out then I will get an aftermarket tip that has a certified spark arrestor in it. There are a lot of neat forests around here and the last thing I want to be responsible for is burning them down.

Beyond that, on the trail, my bike has more than the needed power for my skill level, so I don't feel the need to replace the silencer at this point. If I get some SM wheels/tires I may get a different silencer for more power, but that isn't in my plans right now.

MaddogFE

Unless people have a temp sensor and can prove the running cooler claim, I ain't buying it.

Barshoe

I do have a laser thermo sensor and it is running cooler!

the_viking

I put a 4.1 on my FE450 and I love it. I run the quiet core with spark arrestor and have all my pipe wrapped. Texas is a tinder box right now, so I'd hate to have the header pipe get near some brush right now!

Barshoe

Nice wrap job!

Duken4evr

I took my pipe apart and learned over on KTM Talk that that these bikes either come with a KTM style can or a Husaberg can. Lucky for me mine came with the KTM can. The KTM can is a straight through design, with a turbine style spark arrestor. It is simple to mod for better flow while still retaining spark arrestor capability.

Here are the pics.



Front section



Front view of spark arrestor



Rear view of spark arrestor



I wound up removing the star nut and restrictor disc thingies from the end cap and shortening the tube on the end cap back to the angled brace visible in the top photo. It seems to flow well, my guess it is on par with an FMF Q. It is louder, but not bad. Perfect thumper sound actually, to this rider's ear.

This is the Husaberg style can (from the manual)



The cans have different part numbers on them, the KTM one is stamped Husaberg, but also "KTM Krizman spark arrestor". As you can see from the diagram, the Husaberg can is a bit of a nightmare. If I had one of those, I would just replace it with an FMF straight away. You could shorten the end cap tube way down, but then it likely would not be effective as a spark arrestor.

Gotta love the torx screws holding these things together. No pop rivet hassle

joao

Hi,

Does anyone know if a stock can from a 07 250 SXF will fit the berg?

Ruger

Those with the FMF 4.1, how much louder would you say it is than the factory can? 10 percent louder? 20 percent?

Back to the title of the thread, I'm unclear about what modifications can be made to the factory can besides simply removing the screen at the aft tip. Could somebody please be specific about the mods they've made, and comment on results?

Barshoe

I have one and I don't consider it any louder then stock.

Ruger

Somebody in another exhaust thread makes the claim that a "reflash" is necessary if you change from the factory can to the FMF. In your experience with the FMF 4.1 is this true or false?