Serious question, need accurate answer. No guesses. I am thinking of making my own carburetor o-ring out of rubber fuel line if I have the right size. I know that the type of line I want to use can withstand around 200 degrees fahrenheit, so let's make that a starting point. Does the intake typically get hotter than much hotter than 200 degrees. Let me clarify: not where the intake meets the engine, but at the end of the intake, where the manifold meets the carburetor. I have a stock intake that has not been modified. A brand new engine that has only been ridden a few times, mostly for test runs. It has no issues that I am aware of. The main thing holding me back from going for a cruise is that I suspect a small air leak. I did have an air leak that prevented the engine from running at all. Thought I had it licked, but I think it is sneaking back up on me. So, will the end of the intake manifold melt the fuel line? I know SBP expansion chambers come with pieces of rubber stuff to use when putting them together. I figure if that stuff can withstand exhaust heat, a little fuel line should hold up to heat from the carburetor.