likely made of a different material
The end of the of the exhaust which has the most likely chance of coming into contact with the passenger will reach a temperature of up to 250 degrees c (482 f). Most exhaust pipes have shielding, to prevent accidental burns, but these too can get hot but to a much lesser degree (up to 60c).. source: "Case studies in contact burns caused by exhaust pipes of motorcycles" The part of the exhaust closest to the engine can get up to 400 degrees c (750 f), but is relatively hard to get to.
If your talking about it doing that after you have turned off the engine then yes. That's just the hot exhaust pipes and catalytic converter contracting as they cool.
That's all down to how hard you run the engine. They can get glowing hot up by the exhaust ports.
If you do short trip driving moisture collects in the exhaust as it doesn't have time to dry out and then you get the water coming out of the tailpipes, the hot gasses from the engine and the cold pipes when first started creates moisture.
Pretty damn hot i burnt my leg on one three years ago and i still have a huge scar.
If your exhaust pipes by engine get red hot you have a vacuum leak that will make it sluggish
I'd be checking the oxygen sensors
Engines run by burning gas fumes- fire is hot- exhaust is therefore hot. Hot gases running through metal pipes will make the metal hot. Hence the reason for "Hot, do not touch" stickers on many small engine exhausts.
Due to the type of metal used in the production of the exhaust pipes, it is very normal for any motorcycle exhaust pipe to turn red when running, especially at an idle. When the bike is moving the air cools the pipe. That is why the street bikes have chrome covers, so you don't see the red/blue pipe.
when the engine and exhaust pipes are cold, the hot exhaust will cool and moisture will condense on the exhaust pipe and drip out. Remember basic chemestry. Automotive fuels are hydrocarbons. The hydrogen molecules in the fuel turns to very hot water vapor when the fuel burns. What you are experiencing is very normal.
Copper is used as hot water pipes because the copper will not corrode when the hot water goes through the pipes
The petrol holder could leak and a spark could ignite it. The hot exhaust pipe could also cause petrol to ignite.