Sounds like a dumb question - even to me. But that's never stopped me before...

I'm in the garage with my KLX torn apart awaiting shipments. I'm thinking it's too bad kawi puts this dog of a can on a great little bike. Too bad they don't treat it like a KDX which has a great little silencer off the showroom floor. A tad heavy, but aftermarket silencers don't improve the power one little bit.

It occurs to me that I still have the (brand spanking new) KDX stocker on the shelf. I bought the bike with an FMF turbinecore installed and kept the stocker when I sold the bike. So I hold it up to the KLX frame and exhaust and it's nearly a perfect fit. A 3/4" extension to the midpipe and it is an exact fit.

Now, the big question - are the internals severely different from a 2T to a 4T? Something tells me yes, or I'd see it all the time.

Anyone ever pulled a switcheroo like this?

 

You know...that's an interesting question. In all my years of owning bikes, racing bikes, and even working part time as a mechanic at a shop for 15 years, I don't think I've ever heard this question or seen someone install a 2-stroke muffler on a 4-S. I certainly have no input based in fact to provide, but it will be interesting to see if anyone does.

I do have a couple of concerns. We all know the pulses from the 2 different engine designs are quite different. Not sure of the engineering principles on the muffler design effects, but we all know the head and main pipe design is dramatically different. This makes you think the design in the mufflers might be different. Also I wonder how the "buildup" issue in a 2-S muffler "might" require a different design. The oil and carbon going down a 2-S pipe is greater, so...?

Still, I haven't seen the insides of a 2-S muffler in decades, so...?

 

Let r rip tater chip

 

The stock KDX muffler uses mechanical baffles, it has no packing to replace. I say give it a try. It will probably smoke a bit at first due to the build up of 2 cycle spooge in the muffler being burned off by the hotter 4 cycle exhaust. It also has a nice turn down tip. Let us know how it works.

 

Two stroke silencer cores are smaller in diameter compared to a four stroke exhaust. Try it it might work

 

The design of a 2 cycle muffler is completely different than a 4 cycle. The tuned area is approximately 1/2 the distance from head, since it is firing twice as fast. Also the 2c has a enclosed cone to pack the cylinder that a 4c does not need unless tuned exactly.
That said, if the KDX power band was at about 3500rpm, the pipe may hit big time at about 7000rpm on the KLX. Don't think it will burn anything up for a try though.

 

I'm gonna give it a try. I'd like to complete the free/cheap mods and check performance with the stock silencer. Then I'll change out the muffler and see what it changes. 1st I have to find someone to weld on an extension for me.

The KDX muffler is probably the best around to try as the KDX rides more like a 4-stroke than most smokers.

Either way, I have nothing to lose as it's just sitting there and they sell for nothing. Perfect experiment as long as it doesn't burn my bike to the ground...

 

Durielk,

The cone you speak of is part of the expansion chamber. He is talking about using the muffler.

 

Woops, I was thinking old school 2c mufflers... nevermind.

 

and those cones, there are two of them, are convergent and divergent