Here's some interesting info on epoxy.
Y'all might know I had a high velocity ported head on my bike for years. I had partially filled the intake port with JBWeld to reshape the port. well after about 5 years, the epoxy was breaking down from the cleaning agents in ethanol fuel, and I had to replace the head. I did this early 2013. Of course there was epoxy in the combustion chambers, piston top, and back up into the carb throat forward of the butterfly. I meticulously cleaned all of it from the cylinder / pistons, and carbs. Of course the new head was immaculately clean.
So fast forward to yesterday. I'm doing some fine tune jetting on Shoodaben, and had to pull the carbs. guess what's all built up in the front throat of the carbs? you guessed it, JBWeld. I don't know where it's coming from, but obviously carried back to the carbs by reversion pulses. I cleaned it all up, but still, this stuff is tenacious and seemingly impossible to get rid of.
My advise is to be very very careful with choosing tank sealer epoxies, as most of them were formulated before ethanol fuel and today's cleaning agents. Seems like an accident waiting to happen.
BTW, if you're interested in the some hotrod work, here's a video of the ported heads, pistons, etc. Cool stuff for hotrodders - Steve
https://www.youtube.com/watch?v=qIR2eEqeSiM