Expansion chamber cleanout?

[Tillerman6]

So here is the last part to be burnt out or cleaned in some way.  I was thinking maybe some drain cleaner?  Drano or something like that? MEK?

As you already may know, the exit hole is very small.  So this does not lend itself to cleaning with a scraper or screwdriver.  I have to go and get two more gallons of degreaser and soak this thing again overnight.  but any thoughts are much appreciated.

[b40rt]

Steel or alloy ? Either way it's got to be cut open and re-packed.

[Tillerman6]

6 minutes ago, b40rt said:

Steel or alloy ? Either way it's got to be cut open and re-packed.

So what is inside there that has to be re-packed?  I can see where someone has re-welded part of a seam, but it is only about 5 inches long  and it's on the tail end under the round exhaust exit hole.  There again hard to get a good picture of it with everything being black already.

 

I have a mig welder of my own by the way.

 

Sounds like you have already done that job a few times?  Tell me all about it please!

 

So are you saying that it is a waste of time to soak it in anything? or just try to bake it /burn it out?

 

[b40rt]

Generally, inside there is a perforated tube ( usually solid with sh@t ) surrounding this is packing, glass fiber or similar. If it's steel burn it out. My preference is to cut a window and fit a plate to make repacking easier in the future. I use rive nuts and good quality silicone to seal. 

[Tillerman6]

30 minutes ago, b40rt said:

Generally, inside there is a perforated tube ( usually solid with sh@t ) surrounding this is packing, glass fiber or similar. If it's steel burn it out. My preference is to cut a window and fit a plate to make repacking easier in the future. I use rive nuts and good quality silicone to seal. 

OK we are getting warm now.  Do you mean remove the glass packing from the big expansion chamber and then burn it out with all the guts removed or what?   I am talking about the large expansion chamber, not the smaller tail pipe.  The smallerspark arrestor/ tail pipe did have a small tube inside that was full of crap, and it was wrapped with fiberglass, (see other thread) but it just slides right out of the spark arrester.

Are you saying that the large expansion chamber has a second tube  inside with packing around it and it is all welded into the big expansion chamber?

I really need X ray vision to see what is going on inside there!   I hate to cut into mine unless I know it HAS to be done.

The only real restriction that I can sort of find is the one in the spark arrester.  It was almost blocked. maybe 75% blocked. 

How do you tell when the expansion chamber itself is blocked or needs to be re-packed if air will still flow freely thru it?  Or is it just one of those things that you do while you are cleaning the whole system out?

 

 

 

 

 

[b40rt]

48 minutes ago, Tillerman6 said:

 

Are you saying that the large expansion chamber has a second tube  inside with packing around it and it is all welded into the big expansion chamber?

I really need X ray vision to see what is going on inside there!   I hate to cut into mine unless I know it HAS to be done.

The only real restriction that I can sort of find is the one in the spark arrester.  It was almost blocked. maybe 75% blocked. 

How do you tell when the expansion chamber itself is blocked or needs to be re-packed if air will still flow freely thru it?  Or is it just one of those things that you do while you are cleaning the whole system out?

 

 

 

 

 

First box is similar to back box in design and function. How do you tell it needs done ?  If you ride the bike regularly the sound is the giveaway, it gets louder and tinnier. Bottom end performance drops off.  You have established the back box is full of crap, chances are the front one is too.

[Tillerman6]

5 hours ago, b40rt said:

First box is similar to back box in design and function. How do you tell it needs done ?  If you ride the bike regularly the sound is the giveaway, it gets louder and tinnier. Bottom end performance drops off.  You have established the back box is full of crap, chances are the front one is too.

No doubt.  The power was starting to fade and it was getting hard to start.  I will figure out how to do the surgery on the front box, but I was hoping that someone has already done a TY 250 and they had the inside knowledge to help me not cut in the wrong place. 

 

I have been washing out the back box (silencer/spark arrester) with some purple power and most of the crud is coming out pretty easily.  There is a restriction near the mid point with a metal cone that points towards the engine, and around that there are some small orifices that let the gasses in, but they are very restricted and the pipe has a weld close to the restriction.  I am trying to poke some wire down the oriifices but about the largest wire that can make it thru there is an .035" piece of mig wire.  Could be the design or it could be more crud.

 

The Degreaser fluid seems to pass by easy enough, but that is moving slow compared to what the gasses will be doing when the bike is back in one piece. It is soaking for a day or so to see if anything else will be freed up enough to release itself into the bucket of degreaser. So far I have gotten out about 4 chunks of carbon about the size of a peanut and the rest has dissolved into the degreaser and turned it black.

 

If I get brave enough or if someone comments with direct knowledge of where the best place is to cut the front box open, I will tackle that too.   It looks like someone has been in there before me and re-welded the sheet metal shut again.  I don't know if they left the insides stock or just took everything out and left it empty.  Totally black inside and can't see a thing. But it feels a little heavier than it should if it was just a shell with nothing inside.

[copemech]

check out the WES silencers. alsp I myself would not cut the front pipe until first I seen how things go after getting the blocked  rear cleaned or replaced.

Also, I have long wondered why a good long soak in a Hot solvent tank at a local automotive machine shop would not work to cut the crud in the pipe. that is what that stuff does, but it is some nasty stuff!

[Tillerman6]

copemech,

  that soak idea is a good one.  I need to make friends with one of the shops in town that has a hot tank.  It could not hurt anything to try that first.  The goo is sort of baked on so it takes a lot of persuasion to loosen it up.  Thing is you can't see inside to see what progress you might be making, so a lot of people would go a different route on this.  My own soaking "tank" is not big enough to put the whole pipe in at once unless I lay it flat and pour in another 2 gallons or so of Purple power. 

That stuff is working but it works better with agitation.  The little insert for the Silencer tail end pipe still has goo and fiberglass stuck inside and it has been soaking now for about 20 hours.  The goo slows down the action of the degreaser after it works a while, but I think there is enough fizz left to give it one more day in the tub.  Wish it was a hot tub. 

 

 

 

 

[Tillerman6]

What about having  the expansion chamber FULL of degreaser and then using a propane torch on the outside?  It would boil the degreaser right thru the steel shell.  That would also keep the shell from getting too hot.

I just have to be sure the degreaser is not flammable.  I suppose that would be like a poor man's hot tank?  I think I would move the flame around pretty quickly and try to get the whole liquid mass boiling at the same time if possible. 

 

 

[copemech]

actually I believe that the majority of your issues may be resolved with cleaning the fire arrester screen ang repacking that. you could flush the muff with a solvent like gas or laquer thinner, then dry with a air feed. the fine screen on the SA is your choke point. those screens are regulation size you know.

[2stroke4stroke]

We used to bung up one end of an exhaust then fill it with caustic soda solution to decoke it.  Will need repacking after that of course.

[Tillerman6]

12 hours ago, copemech said:

actually I believe that the majority of your issues may be resolved with cleaning the fire arrester screen ang repacking that. you could flush the muff with a solvent like gas or laquer thinner, then dry with a air feed. the fine screen on the SA is your choke point. those screens are regulation size you know.

copemech,

   You are probably right about that spark arrester being most of the problem, but I want to fix ALL of the problem.  I have a mig welder and a small machine shop, so it's not like the end of the bike if some part of the process does not turn out like it should.  I think the expansion chamber will have to be opened up regardless of how the engine runs just for GP if nothing else.  I know it will be a PITA but at least it will not be another possibiliy for trouble down the trail. Also, I think that it was probably junk in the two pipes that was causing most of my engine problems.   The piston and jug were almost at their wear limits, but the noises the cylinder was making were probably more from the clogged exhaust.

I'm just trying to figure out how to make the cuts so that it can be re-sealed with fasteners.  This would be the best of both worlds because it will need to be re-packed several more times before I quit riding from old age. 

 

[Tillerman6]

8 hours ago, 2stroke4stroke said:

We used to bung up one end of an exhaust then fill it with caustic soda solution to decoke it.  Will need repacking after that of course.

Well that sounds do able.  Were you working on a TY 250 for that decoke process?  If so, when you re-packed the expansion chamber you had to cut it open?  So where did you cut it and how did you seal it back up?  What sort of mixture did you use for the caustic soda?  What was the result of all that hard work?

 

I have 2 pictures attached to this email.  they are labeled "1" and "2" and they are on opposite sides of the rear end of the expansion chamber.  would you look at them and tell me if those outlined areas are where you would cut if you were doing it all over again?

 

Thanks in advance- Newbie to expansion chamber "surgery"

[Tillerman6]

News flash!

    I had some of the old oil soaked glass that was removed from the spark arrester and just to see what would happen with a propane flame directly on it I tried to burn it up.  The oil part burned pretty clean, but the glass would just glow orange.  I don't think you could call it "melting" per se.  It did ball up a bit around the edges, but it never got hot enough to get anywhere close to a liquid.

 

So if it is under a wire mesh it will probably stay there.  So it looks like it needs something like Acetone or some other flammable solvent to get it on fire and burn out all the old oil deposits.  Just enough to wet the insides and then stand back and let it burn out.  Once the oil in the glass ignites it will stay lit for a while.  Might need some air to keep it going?