I've never done this before and couldnt find a picture of what and where are you suppose to drill out on the stock exhaust to make it better.

 

I bought a deep metal cutting hole saw the same size as the outlet i was going to weld back in. Mine was 1 3/8-inch. I ended up drawing a circle onto the end of the muffler the same size as the new end piece that I was going touse as the outlet. I then drilled a series of small holes (1/8-inch) around the inside perimeter of this circle and cut the metal between the holes with a dremel tool. (the hole saw would not work as the pilot drill was only 1/4-inch and the stock hole in the muffler is 1/2-inch and the drill would just wonder too much)..Turns out the 1/2-inch stock outlet is actually a pipe that is connected further inside the muffler to another baffle.which.you will have to break the pipe away from the inside baffle by wiggling the pipe back and forth until it succombs to metal fatigue and breaks. NOW you can use the hole saw and drill the 1 3/8 holes through the two remaining baffles. You will then see a cylinder with a series of holes in the side..I believe this is the spark arrester?--I stopped here and then welded in the new end piece. (note--I drilled through a total of 3 walls one of which is the end of the muffler itself.) I also installed a jet kit and opened up the airbox lid after doing the muffler modifications..I did not ride the bike until all work was complete for far of running it hot and damaging the engine.

 

very nice! I did it the easy way...get yourself a 1/2" , 12" long drill bit at lowes or homey depo for $18, stick it in the end and just drill. you'll hit two plates and your done...easy, alsthough not the perfromance gain of mudjunkie's setup. also, search this forum as several people have done exhaustotomys and posted pics with them.

 

Here, this should explain it all:

https://www.kawasakiforums.com/m_192966/tm.htm

 

I just put a UNI filter on and jetted it with a 122 and removed the airbox lid. If I drill out the exhaust like this would the 122 jet work alright with it?

 

depends on your bike, your elevation and the brand jets you use...but 122 sounds pretty lean for no airbox lid. how is it running now with the 122? if you are running on the rich side you should be okay to drill, if not bump it up. a number of us had to get at the carb several times to tinker with the jetting, it's not fun but a necessary evil.

 

It seems to be running alright now, I'm around the northern indiana area, should I jump up to the 125 then?