EXTREME heat from exhaust pipe

I purchased a DB Dawg to run in my Delta exhaust as this is the only way I could use a Spark Arrestor. It worked well to quiet the bike down as well. BUT, I have an issue and a concern because in one 30km ride, the DB Dawg actually melted. Half of the piece simply disappeared. What would make the bike run so hot. Aluminium melts at 660 degree C which is way hotter then the exhaust gases should be. Should I be in a panic about what may be going on in the engine???

My coolant is topped up and the bike doesn't seem to run hot. Coolant temp sits around 95-98C when running it hard in the bush and I have seen a MAX temp of 102C.

FMF programmer, opened air box, and a full Delta system. The strange part is that my buddy actually told me he thinks I am running rich as he could smell gas when riding behind me.

Thoughts PLEASE as I am stressing out over whether or not I am cooking my motor!!

Take pictures and post them.

My first thought was "too rich" as well.

What numbers you running on your programmer?

Might you be getting secondary combustion in your exhaust pipe due to running too rich?

I will take some shots of the Dawg tonight. Didn't get a chance yesterday. Settings on programmer are factory settings stil, the bike is running great so havnt played with the settings. I am gonna have to now though.

Does the bike have to be running to adjust EFI prorammer or just on?

Generally bikes run cooler when rich and hot when too lean so I would be surprised if it is a rich condition that caused this.

Coop wrote:

Generally bikes run cooler when rich and hot when too lean so I would be surprised if it is a rich condition that caused this.

Yes....but if there's some still raw gas in the pipe, and it's plugged up on the very end, it's possible the gas in the pipe is reigniting and melting things.

motokid wrote:

Coop wrote:

Generally bikes run cooler when rich and hot when too lean so I would be surprised if it is a rich condition that caused this.

Yes....but if there's some still raw gas in the pipe, and it's plugged up on the very end, it's possible the gas in the pipe is reigniting and melting things.

I have first hand experience with this on a 600cc crotch rocket powered go-kart.

Too rich can indeed melt muffler guts. Too lean will generally make the header glow before it starts taking out mufflers.

Ok I concede. I wasn't even thinking about unspent fuel igniting in the silencer.

I find this just crazy!!!!

Gonna take a look into this today. Should have time this afternoon. Figure I should check out the air filter and then mess with the EFI setting. Will keep y'all posted

A restricted exhaust will cause high heat in the muffler. A rich condition will also cause high heat in the muffler and has a cooling effect in the engine. A lean condition will cause high temp in the engine and a cooler muffler.

That's why Pyro gauges are mounted so close to the exhaust ports, you want to know what is going on in the engine.