Temperature of intake manifold/carburetor?

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bigbutterbean

Active Member
Jan 31, 2011
2,417
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Lebanon, PA
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.
 

sketchman

New Member
Mar 23, 2011
168
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WV, USA
Pretty sure those "rubber" stuffs with the SBP pipe are silicone. Much tougher than rubber when heated.

Just thought I'd clarify.
 

Pilotgeek

New Member
Apr 6, 2011
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Green Bay, WI
I have successfully used rubber fuel line as engine pucks (fin spacers to reduce noise). That is, direct contact with the cylinder fins. No melting or anything weird.

That far back on the intake, it doesn't get very hot. There's air flying through there, which naturally cools it a bit. I've used electrical tape in the past on that portion of the intake to seal it, and it has not shown any signs of heat damage. I doubt it gets over 120 degrees ever.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
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Littleton, Colorado
Run your bike then reach down and put your finger on the intake where the carburetor attaches. I think you'll find it warm, not so hot as to burn you.
200 degrees is darn hot. If your carburetor is that hot, you have problems.
Long durations of idleing in high ambient temperatures could effect the situation but under normal riding conditions the intake/carb area stays relatively cool. Certainly a rubber 'O' ring will easily withstand the heat.
Look at it this way; even if you made a gasket out of paper, it wouldn't burn below 451 degrees.
Tom