Note: All of the images below can be viewed full-size by clicking on them.

I ordered the Muzzy's pipe because I was looking for a replacement for my scratched stock muffler, and wanted something that would sound and look more sporty.  After much consideration, I chose the Muzzy's pipe based upon it's looks, quality, and the fact that it bolts to the stock flange. 

Here's a "before" picture with the stock pipe for reference:

The installation process if very simple, and only takes about 10 minutes total.

Step 1: Remove the stock flange cover with an allen wrench

Step 2: Remove the 3 bolts holding the muffler to the flange

Step 3: Remove the bolt holding the muffler to the upper bracket, and remove the muffler

Step 4: Cut off about 1/2 " off the end of the exhaust pipe with a hacksaw.  (This is not in the Muzzy's instruction sheet, but is necessary to get it to slide all the way on)

Step 5: Slide the new pipe on, and bolt it to the upper mounting bracket using the bolt you removed previously

Step 6: Bolt the new pipe to the stock flange using the 3 bolts provided with the new pipe, using an allen wrench

Step 7: Reinstall the stock flange cover

You're done!!!

The Sound:

The Muzzy's pipe is much louder than the stock muffler.  It has a very deep and rumbling sound to it.  I think it sounds great, but some people may not like it if they don't like the traditional sportbike sound.  The ZR-7 sounds like a roadracing bike with this pipe.  

Performance:

I rode twice in succession with the Muzzy's pipe and the stock muffler, so I could accurately assess any performance difference.  The bike runs virtually the same in the low to mid rpm ranges (below 6,000), just louder.  Above 6,000 rpm, there is a noticeable increase in top-end power with the Muzzy's pipe.  The engine seems to be breathing easier and races to redline faster than with the stock muffler.  The Muzzy is about 1/3 the weight of the stock muffler also.

Rejetting the carbs:

Muzzy's says that rejetting is not required, but can yield a few more horsepower.  They recommended shimming the needles slightly and turning the fuel screws 2 1/2 turns out.  I ordered the Holeshot jet kit, which comes with a K&N filter, #110 main jets and needle shims instead. 

Good luck! 
Jarel Jensen

Muzzy's Race Pipe

Pros:

• Looks great!
• More top-end power
• Sounds like a roadracing bike

Cons:

• May be too loud for some
• Expensive (over $500)