My 2000 bmw had one. I spent a lot of time removing the cat from the original exhaust. In the end, I gained nothing and it was still good when I removed it.

The only thing I could notice was the smell from the heat and the folks behind me could smell it before I took it out.

No gain, no loss. Might as well leave it there and keep the air clean.


Things that could cause the exhaust to over heat are LATE ign timing, cam timing off and of course running rich. Its probably just normal heat.

The exhaust on my 09 will melt bungee cords attached to the provided tie down on the exhaust side.

David

 

Totally stock 2009 exhaust on my KLX gets ripping hot under normal driving. It stays hot too, long after the bike has cooled down that muffler is still scorching hot. With factory jetting if I run the bike with the choke on to warm it up for a couple of minutes the headpipe will glow red, visible in the dark only.

These new bikes are meant to use the exhaust system as an afterburner combustion chamber. Expect high heat. Not all cats need extra air to reburn the pollutants, I would say most modern vehicles use a cat that requires no air supply to work. Just high temps and pollutants.

In the OP's case, you are running rich with the stock exhaust. If there's enough air then it will be burning in the pipe.

 

Thanks guys. I've taken off the air intake to the exhaust and will see what difference that makes. But I can't believe that this is normal exhaust temp, as I doubt Kawasaki would design the bike so that the muffler would melt the air intake box and fender.

Could rich running cause this? I pulled the plug and it looks fine.

Tom

 

Yes, as I said before, running rich could cause your situtation. Kawasaki didn't design the system to compensate for a rich running engine, it was designed to run properly and meet emissions the way they had it set up...and not melt plastic on the bike. Who knows what the previous owner may have done to the jetting in the carb. No, it doesn't sound normal at all, but if you dump unburned fuel into an exhaust system with an air injection system, the secondary burn can make things mighty hot...even without a cat.

Unless you're really used to reading plugs, the KLX engine like most modern engines is hard to take conclusive plug readings on...unleaded fuel and other design issues make it tough. A carb really has to be out of whack to notice a large change in plug color nowdays in most engines.

 

I hear you. The jetting is the issue. I don't have the knowledge at present for rejetting the carb, so I'm going to try to live with it as is. I like the power it's currently making. So I'll put some insulation on the airbox to keep it from further melting. Thanks for your help on this.