TY 250 A Tailpipe cleanup advice?

[Tillerman6]

Thought I should start a new thread for this one. The pictures tell the tale better than I can.

All the parts on this one seem to be steel unless there is some aluminum tubing inside the Stainless Steel mesh between the large washer/baffles.?

This stainless mesh is spot welded onto the inner tube and the inner tube is full of about 1/4 inch holes.  You can't see the holes unless you hold it up to the sun light.

I won't burn this part out just to be safe.  It is not caked with carbon deposits anyway.  Just another dip in the degreaser shoud clean it up well enough.   The only problem (and it may not be much of a problem) is the fiberglass packing that was oil soaked.  It lived in the "cup" at the forward end of the assembly.  As you can see it is a mess.  I am leaning towards removing it all together because about the only thing it seems to do is collect oil residue?

One of the photos shows it pryied out with a screwdriver.  I could push it back down if you think it needs to be in there to keep everything from rattleing?

[tshock250]

That's your exhaust packing, you're supposed to change it when it gets clogged, its not there to stop things rattling, its to keep your bike quiet.

[Tillerman6]

So where do you get new packing from?  And is there ANY MORE packing anywhere else that has to be changed out?  Like in the main expansion chamber?

[tshock250]

Any off road motorcycle shop, or online.

[Tillerman6]

6 hours ago, tshock250 said:

Any off road motorcycle shop, or online.

Thanks Tshock250  I am getting a lot of very useful info that I should have known by now, but my bikes before this one did not use any packing in the exhaust, so it was not in my memory banks to use. 

[feetupfun]

The main chamber has packing too. It is a thinnish layer between the outer wall and a layer of perforated steel mesh that follows the shape of the outside. It doesn't actually make much difference to the sound if the packing is functional (dry) or gooey or absent, but it is certainly a lot lighter if it is not gooey. If you heat the main chamber to a high enough temperature, the packing will change from being a fibrous mineral cloth to a glassy viscous liquid. If you do it right, the molten glassy material will flow out of the chamber.

If you are someone who is fastidious enough to want to completely restore the main chamber to original performance, it is possible to cut it apart, remove the perforated metal, remove the gooed up packing and fit new packing and weld everything back together again. There are photos somewhere in the forums of how someone cut theirs apart and rebuilt it.

Edited August 23, 2018 by feetupfun

[section swept]

16 hours ago, Tillerman6 said:

Thought I should start a new thread for this one. The pictures tell the tale better than I can.

All the parts on this one seem to be steel unless there is some aluminum tubing inside the Stainless Steel mesh between the large washer/baffles.?

This stainless mesh is spot welded onto the inner tube and the inner tube is full of about 1/4 inch holes.  You can't see the holes unless you hold it up to the sun light.

I won't burn this part out just to be safe.  It is not caked with carbon deposits anyway.  Just another dip in the degreaser shoud clean it up well enough.   The only problem (and it may not be much of a problem) is the fiberglass packing that was oil soaked.  It lived in the "cup" at the forward end of the assembly.  As you can see it is a mess.  I am leaning towards removing it all together because about the only thing it seems to do is collect oil residue?

One of the photos shows it pryied out with a screwdriver.  I could push it back down if you think it needs to be in there to keep everything from rattleing?

US market spark arrestor, remove it and the engine might run just a little more crisply. Not sure what the State Troopers reaction might be though.

[Tillerman6]

9 hours ago, section swept said:

US market spark arrestor, remove it and the engine might run just a little more crisply. Not sure what the State Troopers reaction might be though.

I need to keep the spark arrestor intact.  We have so many natural (lighning) caused forest fires up here in the summer, I would not ever want to take a chance starting another one.  right now I'm just waiting for the new packing to show up.

[Tillerman6]

10 hours ago, feetupfun said:

The main chamber has packing too. It is a thinnish layer between the outer wall and a layer of perforated steel mesh that follows the shape of the outside. It doesn't actually make much difference to the sound if the packing is functional (dry) or gooey or absent, but it is certainly a lot lighter if it is not gooey. If you heat the main chamber to a high enough temperature, the packing will change from being a fibrous mineral cloth to a glassy viscous liquid. If you do it right, the molten glassy material will flow out of the chamber.

If you are someone who is fastidious enough to want to completely restore the main chamber to original performance, it is possible to cut it apart, remove the perforated metal, remove the gooed up packing and fit new packing and weld everything back together again. There are photos somewhere in the forums of how someone cut theirs apart and rebuilt it.

Feetupfun,

  Thanks for that reply.  I will be looking for the pictures on here.  The more information I can gather up the better.  I don't want to cut it open any further than is needed.  That oil soaked tin will be hard enough to weld back shut as it is. Someone has suggested rivnuts instead of welding.  Maybe that is an option if the hole is large enough.  I am going thru all the pages of emails and replies and I've got up to page 70. Haven't seen it yet, but it's interesting stuff all the same.  "Heating it up to a high enough temperature"  That is a little scary.  Have you tried a propane torch on the outside at all? or is it more likely to work by putting the whole thing in a wood based fire?

Also the "kerf" of the cut off wheel will be something like 1/32 to 1/16" so probably the best way to patch that back would be a larger piece overlapping the opening a bit and either using rivnuts and high temp silicone or tack welding the lid back on. Trying to butt weld the original piece back in would be a lot harder.   But in any case it could all be done on the side facing the fender, so the patch would not show.

 

[Tillerman6]

Feetupfun and guys,

 

  Here are the pictures I just took that look like possible areas on the expansion chamber that look like they might be in an area where they could be patched back up again without too much trouble.

They  are labeled "1" and "2"   They are on opposite sides.  Any preferences?  I am getting a bit braver now.

 

 

[feetupfun]

The chamber in the photos has not been opened for cleanout previously.

On something like a Bultaco trials bike, cutting out a flap or hatch and butt welding it back works well because there is a lot of space between the wall of the chamber and the cylindrical mesh tube inside, and the tube is only held at the ends. On a TY chamber that technique does not work well because the internal perforated mesh is attached by welding to the outer wall very closely in many places. If you want to clean it mechanically (and I'm not suggesting that is a good idea) you need to cut the chamber in half lengthways, cut out the perforated mesh, fit the packing, weld back the mesh then weld up the chamber.

I recommend burning the chamber clean. Keep it at or below red heat. Some people use a wood fire. I use either a large LPG (Propane) torch or an oxygen-acetylene torch. It should take about 10-20 minutes to do.

[Tillerman6]

16 hours ago, feetupfun said:

The chamber in the photos has not been opened for cleanout previously.

On something like a Bultaco trials bike, cutting out a flap or hatch and butt welding it back works well because there is a lot of space between the wall of the chamber and the cylindrical mesh tube inside, and the tube is only held at the ends. On a TY chamber that technique does not work well because the internal perforated mesh is attached by welding to the outer wall very closely in many places. If you want to clean it mechanically (and I'm not suggesting that is a good idea) you need to cut the chamber in half lengthways, cut out the perforated mesh, fit the packing, weld back the mesh then weld up the chamber.

I recommend burning the chamber clean. Keep it at or below red heat. Some people use a wood fire. I use either a large LPG (Propane) torch or an oxygen-acetylene torch. It should take about 10-20 minutes to do.

Feetupfun,

   That's a much better picture than what I had to start with.  Since the wire mesh is pretty much against the outside wall,  and welded to the outside wall to boot, it sounds like more of a hassle than it is worth to open it up.  If there is anything remaining inside between the wire mesh and the outside walls it sounds like it would not interfere with normal operation once it was burnt and dried out.

Right now it is drying a bit from a soak in the de greaser.  I did not open it up yet, so thanks for that new information. Saved me a lot of hassle.  I will go hang it in a tree and let the de greaser drain as much as possible before I light up the weed burner  - this is from Harbor Freight and has a large flame coming out of it if you pull the trigger. 

 

I would assume that if the pipe is hanging up you would want the fat end down.?  That way maybe something will fall out more easily?  Or does it make any difference?

[feetupfun]

I put the flame through the inside with the direction of flow the same as the exhaust gases. The pipe is lying flat on the ground. After it is cooked and cooled you can tap it and shake it to remove any loose stuff. If you want to try and get the glass to flow out while it is liquid it would be best to get it to flow towards the inlet end because it will get trapped inside at the outlet end.

Don't leave it sit around for long after the burn out or the insides will rust out pretty fast. Refitting it and going for a ride does a good job of coating it.

[Tillerman6]

2 hours ago, feetupfun said:

I put the flame through the inside with the direction of flow the same as the exhaust gases. The pipe is lying flat on the ground. After it is cooked and cooled you can tap it and shake it to remove any loose stuff. If you want to try and get the glass to flow out while it is liquid it would be best to get it to flow towards the inlet end because it will get trapped inside at the outlet end.

Don't leave it sit around for long after the burn out or the insides will rust out pretty fast. Refitting it and going for a ride does a good job of coating it.

Well I would have screwed that up for sure. I was thinking of hanging it up on a steel coat hanger  with the outlet end down.  So that was mistake #1.  The other mistake would have been heating the outside of the pipe with the propane weed burner instead of the inside. 

 

SO YOU DON'T HEAT THE OUTSIDE AT ALL???

And if the only way to stop the rust is to fire it up on the bike, then I will have to wait for the cylinder to come back from Millenium. 

Could I use some fogging oil for an outboard motor? and then plug up both ends until the cylinder gets back on?

Thanks again for all the suggestions.  I do really appreciate your help!

 

 

[Tillerman6]

I don't know if I have ever tried to melt any fiberglass with a propane torch before.  If the clean glass that shows up for re-packing the silencer will melt with propane, then that will be the acid test.

If that melts, then melting out the old stuff in the expansion chamber will seem a lot more doable.    Good thing it is not Kaowool in there as that stuff will not melt at all at least not up to 2500 degrees F.  Propane is about 1350F so it would not do anything to Kaowool which is used for foundry furnace insulation.

I am sure that the aceytaline rig would do it, and that will go to 6500, but I don't have that setup any more.