SR question: Anybody cut open the silencer?

i don't know about your bike but on most mx bikes you can usualy just drill out the rivets to get a silencer apart and then just rerivet it back together when your done.

Look for a bolt on the underside of the silencer to drain excess oil. take it out and get a drip pan.
Gordo

thare isnt 1 rivet on the KDX Silencer, I have a 2003 KDX 200..and there isnt just 1

jaguar,

I have an 89 SR. I completed this job over the new year.
-Drill out the two rivets at the back end of the pipe (top and bottom)
-This will allow you to remove the end cap.
-Drill out the 6 rivets in the front end of the pipe.
-The inner section of the pipe can then be removed to the rear (may require some grunting and cursing)
-Cut off the old packing.
-Clean up the perforated pipe.
-Re-wrap the pipe with new muffler wool.
apply silicone sealant to the flange on the inner pipe where it
-Re-install the inner section (swear if you need to) locate with rivets but do not rivet yet.
-install the end cap and align the inner pipe (this is why we didn't rivet as the inner pipe can be out of line)
-get out the rivet gun and clamp it back up.

Hi Jaguar

Mine is just like yours and I am looking to clean it as well. The "in" end has been installed when the "out" end was not yet welded on and pop riveted in place ... removing these rivets would not give access to the guts just allow the end to fall in!. Unless you can advise me differently I intend to cut mine about 2 inches back from the tail end weld. I figure I can then drill out the pop rivets and take the whole thing apart. I think this is a very restrictive muffler and intend to "free it up a bit". Let me know if you have made any progress.

Guest
New Zealand

Just had a closer look at my silencer. I am sure that it is a stock muffler. It has KHI K 260 stamped into the side.

Could possibly have been modified by a previous owner.... Lucky me.

Looks like they have cut the end cap off right next to the weld (just forward of it).

If you cut carefully around, only cut through the body of the silencer as the end cap slips inside it for an inch or so. This should allow you to drill some holes and rivet it back on.

Well I done it!... What a mission.
I cut the muffler about a quarter inch back from the manufacturers weld.. I was careful not to cut any deeper than the thickness of the aluminium (about 3/32nds) this worked well though I would cut closer to the weld if I did another one (say 1/8). this allowed me to withdraw the end plate with it's location guide intact. If I had cut through the end to a greater depth I would have sliced the guide in half.

Next I drilled out the rivets at the in end (these hold the bowels of the muffler in place) I then had to saw off the input pipe to the muffler as the bend won't fit through the hole (it was obviously welded on after the muffler was assembled)

And slid the whole sorry assembly out of the muffler tube... Very simple and sweet design.. The muffler is divided in two slightly forward of the middle the gasses from the engine are piped through the first chamber and released in the second chamber they then flow back to the first chamber and are piped out to the world. (so they basically go round in a circle then come out)

This arrangement is surrounded by a perforated drum which is wrapped in fibre glass. The perforations in my drum were all partially blocked and many were completely blocked and the packing was fairly solid with carbon. No spooge at all. I tried a few options to open up the chamber and found the best way is to chisel out the four welds in the tail cap (this bent the cage a bit but it is easily straightened. With these welds broken the end of the drum came off and I could clesrly see the guts of the system.

There is no real potential for this muffler to block up (which I was concerned about) The carbon seems to accumulate around the mesh drum and in the packing where it prob does not effect the efficiency of the muffler much at all.

In any case I cleaned out my perforations all gazillion of them replaced the packing (I used Chopped strand mat) and drilled a few judicious holes to aid the free flow of gasses. They told me in the shop that these mufflers are a bit restrictive.

Welded the whole thing back up .. no noticeable difference in power or sound.

My muffler weighed 2.1 KG when I stripped it and just over 1.8 when I re assembled it .

Bit of a waste of time but I'm glad I did it at least I know it's good for another 10 years (I hope)

Cheers


Guest

if your silencer is all-steel (not aluminium) then the easiest way to clean it out is to burn it out rather than cut it open. Remove the silencer from the bike, takei t outdoors, heat up the inlet section cherry-red with a welding gas torch then blow compressed air into the inlet end of the pipe, keeping the flame on the outside and moving the "hotspot" along as the burn occurs inside. This will expedite the burning clean as the flame path travels through the oily carbon inside, fanned by the compressed air stream which should be continuous. A huge amount of smoke will be produced, and when this tails off the silencer is essentially clean & can be gently tapped to shake out the ash, repainted and replaced on the bike.

I used the foaming type spray oven cleaner to clean mine. The stuff expands when you shoot it in the ends, and drain hole...... I figured it would contact most areas in the assembly.

Guest from NZ. Thanks for the description.
Looks like the internals of my muffler have been modified too. Mine only has the perforated pipe straight through with packing around it.
That's why I could pull the internals out without cutting off the inlet pipe.
Still bloody quiet though.

Jaguar

The holes in the mesh allow the exhaust access to the padding around the outside of the muffler (sandwiched between the aluminium outer and the mesh steel of the muffler insert) if all these holes were filled with carbon the muffler would still flow freely (it may not be as quiet).

Cheers

Guest (New Zealand)