DIY Muffler...

[TLDV8]

There is also carbon tube available.
I think the tube i used was made in Rotorua,but there is also this place in Auckland.
The resin was strong enough to be able to turn the tube ends in the lathe.

http://www.carbon-tube.com/index.php

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[SARGE]

The inner baffle is a perforated tube, they perforations aren't just holes, but little flow restrictors I guess you'd call them. You can get lengths of it from somewhere like www.autobend.co.nz, or probably better for a welly man, www.neptunemufflers.co.nz. But you're right, they're essentially a baffle, and outer tube, some packing and some flanges

mufflers have packing ?????

[imdying]

I purchased a pair of aftermarket mufflers for my old 750 twin that had a perforated core system (straight through) that were too loud. I got a bit of muffler pipe and cut slots in in and punched them inward to make a pair of insert baffles as per attached photo. They knocked down the sound a lot (the first set too much so I made a shorter set). I noticed no difference at all in performance with or without them. The theory is that they disturb the flow a bit while still being a 'performance' baffle. Should look like a set of 'hills' when looking from the direction of flow -engine end (not 'caves').
If yours is a bit loud whip up one of these for inserting in the end.

Thanks for that mate, I might need something like that for warrants....


So, an update. Made my first cardboard 1:1 model last night and fitted it. Was a bit tight, have a revised edition coming tonight. Think I'm going to go for a single outlet instead of twin outlet though, just to get the volume in silencing material :/ More research!

[MSTRS:Me]

...., I packed the core with fiberglass mat and chopped strand, and taped around the outside to pull the fiberglass in tight so it would fit in the outer tube.

Good point here - packing should be reasonably loose, and certainly not wrapped tight on the perforated tube. What you are trying to achieve is exhaust flow essentially going straight through, but the sound waves expanding in the muffler by going through the holes at the 'front' of the perf.tube, filtering through the packing (which is why it should be fairly loose/uncompressed) then re-entering the perf. tube towards the rear and then exiting the whole system.
This is essentially the 'Coby' design (what the Americans call a glass-pack). If you get it right, you will achieve enhanced performance with an acceptable dB

[imdying]

There is also carbon tube available.
I think the tube i used was made in Rotorua,but there is also this place in Auckland.
The resin was strong enough to be able to turn the tube ends in the lathe.

http://www.carbon-tube.com/index.php

.

You bastard, stop showing me that shit

[R6_kid:Me]

mufflers have packing ?????

i thought thats what dover did when you left your bike unattended in his presence.




Whats a good thickness of carbon-fibre to use for and exhaust? I've finally devised a cheapish way to get an M1R replica pipe made with no hassle, but no really sure whats a suitable thickness of carbon to use.

[AllanB]

Yep - slid inside the existing pipe and I held them in with a stainless steel seft tapper. I'd also welded a bit of rod in the centre to grab onto to make removing easier but this is not essential.

[degrom]

I purchased a pair of aftermarket mufflers for my old 750 twin that had a perforated core system (straight through) that were too loud. I got a bit of muffler pipe and cut slots in in and punched them inward to make a pair of insert baffles as per attached photo. They knocked down the sound a lot (the first set too much so I made a shorter set). I noticed no difference at all in performance with or without them. The theory is that they disturb the flow a bit while still being a 'performance' baffle. Should look like a set of 'hills' when looking from the direction of flow -engine end (not 'caves').
If yours is a bit loud whip up one of these for inserting in the end.

LOL.. It might just help me get my wof in the future with all the noise restrictions.

Thanks for the tip!!!