Aftermarket Mufflers. Longer Midpipe's?

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pdee4t

Hey guys. im purchasing an FMF muffler for my bike but have a question. I have looked up all the possible silencer options available for my bike, model and year(went to go re-pack my other one but the core has broken bits off it)...so already made the decision to buy a new silencer but am confused with fitment.
on my stock KTM silencer, the midpipe(that goes into the exhaust header) is only a short round circle bit, but on the FMF pipes, its a longer piece of pipe/tubing.
So if that's the case, how will the muffler fit on properly?? because if that's the case, as logic would say, because of the longer pipe on the end of the silencer, the silencer wouldn't line up properly to mount on....

in the picture below, you can see the difference...how would that fit onto my header with it being a longer pipe?

U6910054.jpg
 
P

pdee4t

also have a question about the jetting recommendations. i purchased an FMF Q4 silencer.
just wondering what is the recommended re-jetting specs/requirements to run the silencer with? i have checked out the fmfracing.com website 'Jetting Center" but my bike model isn't listed. Its a KTM 450 EXC 2004 model(4 Stroke) for those that don't know
any help or advice on this matter would be greatly appreciated.
 
2strokesteve89

2strokesteve89

pdee4t:
Hey guys. im purchasing an FMF muffler for my bike but have a question. I have looked up all the possible silencer options available for my bike, model and year(went to go re-pack my other one but the core has broken bits off it)...so already made the decision to buy a new silencer but am confused with fitment.
on my stock KTM silencer, the midpipe(that goes into the exhaust header) is only a short round circle bit, but on the FMF pipes, its a longer piece of pipe/tubing.
So if that's the case, how will the muffler fit on properly?? because if that's the case, as logic would say, because of the longer pipe on the end of the silencer, the silencer wouldn't line up properly to mount on....

in the picture below, you can see the difference...how would that fit onto my header with it being a longer pipe?

U6910054.jpg
Click to expand...
As long as it bolts up...I'm guessing the overall length is the same, just slightly longer inlet and shorter silencer body, if it's by application it should work well being FMF puts out a good product.
 
P

pdee4t

ok cool. will just have to see when it arrives i guess.
how about jetting though? do i need to re-jet with it being a FMF silencer and not the whole exhaust/header pipe?
 
2strokesteve89

2strokesteve89

pdee4t:
ok cool. will just have to see when it arrives i guess.
how about jetting though? do i need to re-jet with it being a FMF silencer and not the whole exhaust/header pipe?
Click to expand...
Wouldn't think so....but then your toilets swirl backwards down there....so who knows
 
P

pdee4t

Lol
So I wouldn't even have to adjust my mixture screw setting?
Cos people tell me when you put on an aftermarket muffler, you should re-jet. It's why I asked.
 
2strokesteve89

2strokesteve89

pdee4t:
Lol
So I wouldn't even have to adjust my mixture screw setting?
Cos people tell me when you put on an aftermarket muffler, you should re-jet. It's why I asked.
Click to expand...
Well it may change your exhaust back pressure, but the best way to tell is check your plug after a ride. It should be ashy grey. I would check the plug before installation then after, darker, blacker shows rich, lighter tanner shows lean. But I havn't had a problem with my 2 strokes after a repack or replacement of a silencer.
 
P

pdee4t

ok cool.
my plugs are usually tanned brown, like a pancake or chocolate colour.
if it is too lean or too rich, what jets would i need to change though? the main jet? or needle clip position? and/or fuel mixture screw?
just want to get a bit of an idea of where to start/what's needed incase.
 
2strokesteve89

2strokesteve89

pdee4t:
ok cool.
my plugs are usually tanned brown, like a pancake or chocolate colour.
if it is too lean or too rich, what jets would i need to change though? the main jet? or needle clip position? and/or fuel mixture screw?
just want to get a bit of an idea of where to start/what's needed incase.
Click to expand...
Well the fuel mixture screw mainly influences idle air/fuel mixture, needle position for midrange, and main for overall mixture, so if you have a problem at or just off idle, go with the mixture screw, go with this first anyways as it's the easiest to adjust, if you have a flat spot or blubbering in the midrange, adjust the needle accordingly, and if you still have issues after this you may need to replace the main jets...but like I said, I don't expect you will have any issues. But if you do, it's pretty much trial and error.
 
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