Silencer Repacking Tutorial

[biglou]

After my recent stint as a wannabe U-boat commander, my kTm 2-stroke has been sounding like a clapped out old junker with the end of the baffle cut off. You know: "RACK-ACK-ACK-ACK!" instead of the usual "Ring-a-ding-ding!" That, and the fact that it is right at a year old now, led me to repacking the silencer. I'll tell you how I did it, and illustrate with the digital photos I took along the way.

Step one: Disassemble. Remove the old packing. This is the messy part. Pretty straightforward stuff, just take'er apart and get her cleaned up. It's "spoogerific"!
Tip: Get a plastic garbage bage for the nasty old packing and have plenty of rags around for your hands.

 

[biglou]

Here is the nasty old packing. It is spooge-soaked and still has some water in it from a month ago after submerging the bike. It ain't pretty:

 

[biglou]

Take a wire brush and scrub the core very diligently to get all the holes opened up. Mine wasn't too bad, but I have heard of some being completely clogged with carbon deposits.

 

[biglou]

Here you can see the new packing material laid out in preperation to be cut to length/width and then wrapped around the core.

 

[biglou]

Here is the packing material wrapped around the core. I have already trimmed about 4" off the width of the entire roll, and now I will cut it lengthwise as I have enough material to fill the silencer can firmly.

 

[biglou]

Here it is cut to fit, wrapped firmly, but not too tightly, and held in place with masking tape per the instructions:

 

[biglou]

Slide the can back on:

 

[biglou]

Get it seated, line up the screw holes, and button her up! Total time from start to finish: 30-45 minutes.

 

[soquel]

Hey thanks for the Guide! Nice pics. Oh and I have one tip to pass on, to keep that spooge from leaking out of the ends of your silencer, seal them up with a bead of silicone

 

[yz250roost]

wow, so it's not just me who has a spooging silencer problem????? makes me feel better, that's for sure,

 

[bclapham]

i was just thinking i needed to do my silencer and was going to post for advice on the matter.

thanks!

bruce

 

[Jaybird]

Lou,
Great teach. I have a suggestion...maybe two (imagine that)
Take off the whole thing. Pipe and all. You WILL find the creature from the black lagoon in the bottom of the pipe....If he's not there, I'm almost certain you will find his remaints. If you don't clean up his habitat, he will tend to ruin your nice clean packing :) (radiator shop or Easy-off)
Also...jets, my friend....jets are cheap! :)

 

[Senior KX Rider]

Well done lou :)

 

[biglou]

Yes, I forgot to mention about the bead of Hi-Temp silicone for the flange at the base of the core. :)

 

[BRush]

Nice job on the tutorial, Lou. Some things that have helped me:

1) If it's not a major hassle (mine is only two bolts), pull the whole silencer assembly off the bike. This means you can clamp parts in a vise for the various cleaning an rebuilding stages.

2) If it's been a long time between repackings, sometimes the holes in the silencer core can get gummed up. I find that using a propane torch to nicely carbonize any spooge makes everything crumble away easily when the wire brush is used.

3) Once you get everything just right, Measure and record the dimensions of the piece of packing material used so you can pre-cut it next time without thinking about it.

I notice that you cut your packing to exactly the length of the perforated tube. Did you have trouble with it wadding up when you slid the outer shell on? I find I have to cut the length of the packing about 2 inches longer than the tube to account for the natural compression that occurs when I slide on the outer shell.

 

[biglou]

No, I cut it to the exact length, but I could have probably given it one more wrap. It sure sounds better now, though!
BTW-This was my first time, being a relative newbie to all of this.

 

[Matt_H]

Jaybird what does a Rad shop do if you wanna get that old burnt oilly stuff out of your pipe?. And does it discolor a bare metal pipe?. Or is there anything I can do my self to clean it?. Sorry for get off topic but I say Jaybird mentioned it and I didn't feel like starting a new thread. Also very well done BigLou.

 

[Jaybird]

They can boil out the pipe. Likely to cost you 20 bucs or so.
Easyoff oven cleaner will work to a point. Be careful where you do this as easy off is caustic as heck. Try going to the car wash for the rinse after the oven cleaner has worked a bit. I don't think you'll see oven cleaner harm a bare pipe, but it will strip the anodizing from aluminum.

 

[smb_racing]

My pipe was so badly carboned it couldn't be boiled, I took it to the local machine shop and had them bake it and then blow it out. They stuck it in an oven for a few hours and that dried out the old spooge, then it just flakes off the pipe easily. The downside is that it'll discolor most pipes due to the heat (mine's bare anyway) cost about $12. Had them bead blast it while they had it and I coated it with some hi-temp clearcoat, looks nice.

 

[spiderbaby]

I fill up my whole pipe (after taking it off of course) with laquer thinner. I shake it up for a few mins and then let it sit over night. In the morning I shake it a few more times letting it sit a few mins between and then pour it out. After that I run more thinner through it a pint at a time untill it runs clear. Kind of messy but my hands seem to wash up fine. :D

Make sure you use laquer thinner and not paint thinner. I have a 55 gallon drum of the stuff so I am not sure how much it is to buy by the gallon.

 

[biglou]

Bump. Old article!