Expansion chamber cleanout?

[feetupfun]

1 hour ago, Tillerman6 said:

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?

 

Sounds like you are having fun. I don't know what will happen the way you are suggesting but it sounds fairly explosive. I never put any solvent inside and they burn out fine. If you have washed out the gunky oil with a solvent you may have made the job more difficult that it would have been. If you can't get it going with a torch you can always put the whole thing in a wood fire.

I usually have to maintain a draft through the pipe to keep the fire going in there. Oxygen is good but you have to be careful to avoid melting the steel (and glass). Fresh air draft takes too much heat out unless it is slow velocity. A gas flame directed into one end works well to start it up

[2stroke4stroke]

15 hours ago, Tillerman6 said:

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"

I was talking generically, never having done aTY exhaust, we had to do our road bikes fairly frequently running at 16:1 as they were.

The area you have highlighted looks like the most likely spot to me - I would do the back side for the sake of appearance.  I imagine old TY exhausts must be available cheaply on the net, given that most Yams seem to use alloy systems now, if you overdo things.

[Tillerman6]

11 hours ago, feetupfun said:

Sounds like you are having fun. I don't know what will happen the way you are suggesting but it sounds fairly explosive. I never put any solvent inside and they burn out fine. If you have washed out the gunky oil with a solvent you may have made the job more difficult that it would have been. If you can't get it going with a torch you can always put the whole thing in a wood fire.

I usually have to maintain a draft through the pipe to keep the fire going in there. Oxygen is good but you have to be careful to avoid melting the steel (and glass). Fresh air draft takes too much heat out unless it is slow velocity. A gas flame directed into one end works well to start it up

Feetupfun,

 

  The Purple Power is not flammable, as I suspected, but the instructions say not to let the chemical dry on the metal, so I rinsed it out with water and now it's on the barbie to boil out the water. 

 

[Tillerman6]

Another little update-  I am baking/burning out the TY 250 A expansion chamber on my old propane barbque grill.  There is no solvent being used. The contents seem to be slowly burning out the old oil.  The Purple Power treatment did not get all the old oil out, so this is step number 2.

I left the lid open about 2 inches and this seems to give it just enough oxygen to continue to smolder.  It smells like oily smoke.  This has been running for about 4 hours, but I want to continue until the smoke stops on it's own.  Overall the pipe is laying flat, but the curved large end is up, and this is acting like a chimney effect to some degree.

I don't have a deadline to meet so if it takes all day tomorrow too, that will be fine.