kx250f hot muffler

[shart]

I noticed after a short ride the other night, a strong smell coming off my exhaust after I put the bike inside and waited a few minutes and in no time at all my header was cooled off but my muffler was hotter than its ever been before, I don't know whether I should be worried or not, or maybe just watch how many rev limiters i give it from now on any opinions would be nice

 

[mjgnslngr]

on some cars ive worked on, if the muffler is getting hot its caused by it 'loading up' with fuel. perhaps your ignition isn't properly burning all the expended gas??? something to look a i guess?

 

[shart]

on some cars ive worked on, if the muffler is getting hot its caused by it 'loading up' with fuel. perhaps your ignition isn't properly burning all the expended gas??? something to look a i guess?

that would make sense as i do have the fuel turned up quite high, but you would think i would of noticed it before now

 

[best]

Modern fuel injected cars have a catalytic converter that burns any fuel in the exhaust. Excess fuel in the exhaust and the convertor becomes a gasoline powered heater, turning it and all the pipe and muffler after it red hot. Our carbed bikes do not have this and don't tend to get really hot from excess fuel. Retarded timing can sometimes make the headpipe hot, but it does really tend to carry to the muffler.

Four strokes are much different than two strokes, much of the heat goes into the pipe and is conducted by that constant diameter pipe to the muffler. The pipe out of the four stroke cylinder will get so hot that sometimes it glows in the dark and the muffler will burn you or melt plastic. This is normal.

A two stroke makes the exhaust work. Right from when the exhaust leaves the two stroke cylinder it starts expanding. In those cones and fancy bulges make the exhaust gases work and expands more. As you know from physics class or even just spraying air with the air hose, expanding gases get cooler. By the time the2 stroke exhaust gets to the muffler, the energy and heat is much used up, the 2 stroke muffler doesn't get anywhere near as hot as a 4 stroke.

My guess is that you are just noticing this difference between your KX250f and your Blaster?

 

[mjgnslngr]

^^^ a rats nest or obstruction can cause the muffler to overheat. also, the catalytic does work as a 'finisher'(for lack of a better word) if you will, to gather heat from the exhausting fumes that Have burned and Burn the ones that havent. a four stroke bike that is putting out a LOT of fumes would turn a muffler into this Heat chamber and collect heat from the slight restriction that Any muffler has. one of the reason why older cats would plug on vehicles was placement. too far from the exhaust manifold and engine and they cant build the heat needed to burn off the excess fumes and they would coke. the newer car/trucks have cats built into the y pipe or directly attached to the manifold. the principles Should be the same correct?