GPZ Intake and Exhaust Mods

Paul Heim SuprHtr at
Fri May 1 21:33:36 PDT 2009

Reed block-off plates are of no consequence either way when rejetting to 
stage 1 or 3 as far as performance.  They just get rid of unnecessary 
hardware and some exhaust popping.

The aluminum fan is an option Muzzy recommends with their system, since the 
Muzzy headers tend to cook the plastic fan.  I'm not aware of any other 
manufacturers that do this, and no one I know has ever complained.

Paul in Ohio
----- Original Message ----- 
From: "keith fraser" <fraskei at>
To: "gpz list" <gpzlist at>
Sent: Friday, May 01, 2009 8:50 PM
Subject: GPZ Intake and Exhaust Mods

I have been considering intake and exhaust options. I came across this page 
on the muzzy site, , showing the 
effects of different mods on a zrx 1100. It's my understanding the gpz and 
zrx motors are very similar.
There isn't much difference in power between the stage 1 and stage 3. I 
would like to stay with the stage 1 but would like to replace the stock air 
filter with a K&N. The air filter is tiny, only about 2/3rds the size of the 
filter in my old Ninja. K&N doesn't list an air filter for the GPZ, anyone 
know of a compatible K&N part #?
If I did decide to go to a stage 3 would I need to buy the reed block off 
plates? Is there anything else that would need to blocked off or disabled?
Unless I find a really good price on a used exhaust system I will probably 
buy the v&h supersport. It fits my budget and is the only black pipe I have 
been able to find. Does anyone know of any dyno charts for the v&h pipe? Or 
any other pipe and jetting combos?
Also I have seen a couple sites recommending changing out the plastic 
radiator fan for an aluminum aftermarket one, is it really necessary?

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