Engine/Exhaust extremely hot

My 2008 honda rubicon exhaust and engine has gotten hot in a matter of second when turned on. Any ideas on what it could be? I've had this atv for about a decade or so. I just moved back home and it's hardly been touched or ridden. I changed the oil and oil filter. Spark plugs are new. I can't take the spark arrester off because the 3 screws are basically melted on. Any ideas on how i could go about that as well. I've took it in and they told me it was looking okay until I bring it home and within a few days it gets hot.
I burnt my finger on the exhaust pipe on the left side of the atv seconds after I just turned it on. It turns on perfectly fine. It's just the hot exhaust I'm worried about and how I could go about this or what's exactly wrong with it. If someone can help, that would be amazing.
Thanks.