What you'll need:
Patience
An unfortunately blown carb cap
Good epoxy for both metal and plastic
Tooth Picks or Popsicle Sticks
A Clean surface
Sand Paper (Optional, I used 220grit)
Hopefully this doesn't happen to you. This happened to me because the PO rebuilt the carbs and put the air valves in backwards on number 2. Too much pressure caused the top to pop
You'll want to clean the top and the plastic very well. Any oil, dirt, grime and general crap that is present will hinder the bonding process of the epoxy. I use kerosene to clean it out. Just dampen a clean rag and then wipe it down. I also went around the inside and cleaned any other build up I saw and pushed a rag through the central hole and flossed it as well.
Warning: There is a little breather hole inside the top of the carb that cannot be plugged up. If it gets plugged or blocked the carb top pretty much becomes useless. (picture below)
What I did to prevent it from being blocked was hold the carb top on its side with the hole at the highest point. Gravity will always pull the epoxy down and prevent it from blocking the hole.
You'll pretty much want to hold it sideways anyways throughout the entire process because you do want epoxy going down the center either. If anything gets on the side walls it will again make it pretty much useless. I mean it's already useless, but at least it can still be repaired.
Unfortunately I do not have pictures of the actual process. I had to work fast otherwise the epoxy would run down the side or droop.
Since you'll be holding it on the side, think of it like building a wall. After thoroughly mixing the epoxy as per the packages instructions, carefully apply it with the Popsicle stick or tooth pick at the bottom edge (sideways remember) of the blown hole. Apply a little more each time and slowly build up the wall so that it will cover the hole. You may have to rotate the carb top as the epoxy might start to droop down, just be mindful about the breather hole. Once covered you'll still need to hold it on its side. Continue to carefully apply more epoxy over the new top to make it stronger. Once you are satisfied with the amount of epoxy on there, you'll need to hold it on it's side so it can harden enough that it won't collapse as soon as you put it down.
Now if you have it, resist the urge to stick something down the center and press on the inside of the new cap to try and either hold it up or push it out more. This is bad for two reasons. One, the thing you are using could get stuck to the inside of the cap and then you end up pulling it down and doing the exact opposite of what you want to achieve. Two, any unset epoxy could stick to whatever your using and get pulled down and out with it which will drastically increase the odds of something sticking to the side walls of the slide.
Let it set for 24 hours and you're done. You can test the breather passage hole with a can of compressed air. Just fire it into the small hole on the inside at the top of the carb and see if the air comes out through the big passage.
Optional: With the sand paper you can sand down the epoxy to try and smooth it out so it doesn't look as ugly. Wait 24 hours before doing this as well. I also recommend covering the bottom opening of the carb top with painters tape or masking tape so epoxy dust does not get inside.
Note:
The reason for wanting to do is this if you do not have another top and slide to replace it or you only have a spare top. I read somewhere (Randakk's site I believe) that the slide and top are matched pairs and it is not recommended to interchange them.
