Cleaning carbon from inside of pipe

Hey all,

I'm a noob so please forgive any mistakes. I am starting to restore multiple old Yamaha ITs (don't ask). I am cleaning the inside of a Yamaha IT 400 2 stroke exhaust pipe using the caustic soda method. The method requires mixing caustic soda (Drano) with water, filling the pipe, letting it sit and then dumping out the mix and repeating. Seems to be working. Here are my questions: 1. Once I am done since I have used water it seems the inside of the pipe would rust. Is this a problem? 2. Should I coat the inside of the pipe with anything and if so what? 3. Can I coat the inside of the pipe to prevent the rust and if so what? 4. Is there a paint code for the exhaust pipe and engine and if so what is it or better yet where can I find it. Any and all input will be greatly appreciated. Thanks

Arenego2,

I won't be able to ride the bike and clean out the pipe right away but, duh!, I'll just rinse the pipe out with lean premix, hang it up and let it dry. That should prevent the rust. Thanks for the idea.

WD 40 it is. I was just concerned that the WD 40 wouldn't get all the way into the center of the pipe. I have no idea what the center looks like, whether it has baffles, whether it is hollow, tiny elves shooshing the engine noises....