Okay, so I repacked my single MTC exhaust and now it doesnt breath properly. I did not pack it too tightly or put in too much material. The can was empty and loud as heck but is now deep and quieter. Nice. But why isnt it flowing the way it should?

A few years ago I had to re-pack a set of end cans for my Triumph Tiger rat bike. I used this stuff:

http://www.thermalvelocity.co.uk/Sil...FaTMtAodZhUA4g

Really easy to use. Fit loose, get the exhaust up to temperature and it expands to fill the void and provides excellent sound damping. Perhaps it'll help you?

__________________
Simon

Brighton, UK

Sweller, thanks Ill check it out. But why isnt my exhaust expelling the gasses correctly? What is supposed to happen?

Can you post some pictures? It's very hard to tell what the problem is from your description.

__________________
If you can read this you're faster than you look...

Interceptor,
I dont have any pictures. I did use ceiling insulation (budget). But it feels as if the bike isnt pulling clean since the repack.

Are you running with a dB killer/baffle inserted? It is quite likely that the "loose" nature of loft insulation (not as dense as exhaust packing material) has caused some, a lot, or all of it to blow out the perforation on the inside of the silencer. If you've got a dB killer inserted it is likely to trap the fibres as they are release through the perforations, partially blocking your exhaust and choking the bike.

I've had this problem before with aftermarket car silencers: Packing material blew out of Magnex back-box on my old Subaru WRX, which caused poor performance, overheating and a melted cat!

Take the silencer off and dB killer out and have a good look through it...

__________________

I've packed a few cans in my time but without a photo it's all but impossible to guess and when you say not flowing you mean theirs no exhaust pressure?

Pleidades,
Yes I have a baffle on. But if the fibres blow out how can it choke? So the ceiling insulation is more dense? Ok, but I only wrapped one and a half times, so Im thinking it cant be more dense than proper packing wrapped 3 or 4 times.? The bike gets to 150km/h reasonably easy on EO7s but I imagine the exhaust breathes harder. When I opened the can there was nothing in there, only the baffle and tiny traces of old packing. There is definitely a difference in the 'breathing'.

If the baffle is fitted in the end of the silencer, it will trap the flying fibres and block, especially if it is a perforated disc type.

Loft/ceiling insulation is less dense and more fibrous, the fibres are thinner, it's much looser stuff, no matter how many times you wrap it. Baffle packing is a wholly different material; it is tighter knit, with longer, thicker fibres that are often cross-laid to hold it together in the extreme heat and pressure of an exhaust silencer. What you've got to remember is that home insulation is designed to insulate heat (hence the loose fibres to trap air) in a pretty stable environment, where as exhaust packing material is designed to insulate noise in tough conditions. They are designed for completely different purposes and environments.

The more I think of it, are you sure that you are not just noticing the sound difference, a quieter exhaust, which is playing tricks on the mind, subconsciously making you imagine the bike is slower/breathing less well?

__________________

Pleiades,
It could be that I think that but I read somewhere that aftermarket exhausts or packing help get rid of gasses quicker letting the exhaust breath better which adds more power. So I guess I am looking for that.