Caustic Soda (Sodium hydroxide)!

Same stuff used in oven cleaner, but oven cleaners dilute it some. You can get caustic soda in pure powder form but I was unable to find it. I found a drain cleaner that was like 99% caustic soda called "Drain Out" in crystal form, the other 1% was aluminum they added to help clear the drain clogs.

This caustic soda is nasty stuff and can blind you if you get it in your eyes. If you do get it in your eyes flush with water for 20 minutes then seek help! Its best to wear goggles and gloves (PLEASE) to protect yourself from this nasty stuff.

Here's how ya do it.

1. Be creative and plug the larger end (that connects to the cylinder) of the pipe off, be sure it will seal water from leaking. A little RTV around the plug doesnt hurt. Also have a plug ready for the smaller end of the pipe (The end that connects to the silencer)

2. With the plug on the larger end in place... Pure exactly half of the Drain Out caustic soda into the pipe's smaller end using a funnel (with the smaller end facing straight up).

3. After pouring in half of the container then proceed to add water into the small end of the pipe. The pipe will because hot to touch as the water is added. Slowly pure in the water so that there is no splash-up. Fill the pipe completely with water.

4. Plug the small end up. The hold the pipe in hand (be sure the plugs will not come out and drop that crap on you, also hold the pipe below your waist just in case it does open it wont drop on your chest, face or worse).

5. Rotate the pipe around in a fashion to bring all the air bubbles that where in the head pipe up to the smaller plugged end.

6. Now set the pipe back down with the plugged end up and remove the plug, fill the rest of the pipe full of water and plug it back off.

7. let this mixture sit in the pipe for 24 hours. Every few hours invert the pipe so that the caustic soda doesnt settle on the bottom.

8. after 24 hours dump it out into your sink that needs a good clog cleaning LoL. (again wear you goggles and gloves). Take the pipe outside and rinse with water.

9. Repeat steps 1 through 8 using the remaining amount in the drain out bottle because it takes two good times to really get it clean.

10. After the second 24 hour run; Let the pipe air dry for about 2 days. This is very important, because it will cause the inside of the pipe to dry out and the carbon to become really dry and crusty..

After the 2 days of drying; You can tap on it lightly with a hammer on the pipes mounts (so not to dent anything) and watch the carbon come flaking off and falling out. After you tapped as much carbon out as possible, the final step is to install it on the bike and go ride. This final step of riding will knock loose any of the carbon that the hammer tapping did not get.

It works.