Carburetor for a CCW

ProDigit · 04-28-2024, 08:53 PM

I'd start with a PZ30. They're only $25, and easy to get.
Your jet sizes depend on a variety of things, like exhaust system, air intake, elevation etc...

If your bike ran fine before, just use a hacksaw, and saw off the bottom of the oem carburetor. Get a carburetor drill set, to measure the carburetor jet sizes.
Then measure the jet sizes on the new carburetor.
I've noticed that quite often the jet sizes built in the carburetor may say eg: 45 pilot, 110 main, but may actually be off by a few digits compared to a jet kit.

Using a PZ30, allows you to get as close to OEM as possible.
Some bikes have clearance issues with different carburetors.
The benefits of a different carburetor are minimal, unless you really want to eke out the last MPH of top speed.
Quite often carburetors like nibbi, Mikuni, or other, use different measurement units. So their jet sizes may differ from the PZ.
They might also be larger in diameter than the PZ30 (which is exactly 30mm), which may help top end, but may make the bottom end (idle) suffer.

I haven't yet found an in depth review about the differences in performance between all of them, but it's pretty unanimous. Larger mm carburetors run richer, and have better top end. Smaller carburetors run better MPG, and idle, at the expense of worse top end.
And somewhere, your bike's engine can only take so much top end. So replacing a PZ30 with a Nibbi 30mm may, or may not get you more top end.
Every brand is basically a different size. Size being the determining factor on top speed, or good idle.

I see no reason not to go with a PZ, unless you really notice awful performance, which in most cases can be corrected with the correct jet sizes.

RubaSon · 04-29-2024, 11:13 AM

Hello, yes there are clearance issues with the PZ carb because of the long intake. The upper part of the carb hits the mount of the fueltank. With the shorter intake for the pwk it fits fine. I want to get rid of this split thing at the throtelcabel. So thats why i want to go with the PWK not to gain Power. The PZ runs good but not perfect. I tried different Jets the best i found was a 40 Pilot and 105 Main. I still mounted the PWK and startet with 38 pilot and a 120 Main but much to rich. Now i Test a 32 Pilot and 110 Main... I have tuned carbs before but only on 2 strokes thats why i need help because of the different behauvior.

04-28-2024, 08:53 PM	#1
ProDigit Join Date: Aug 2013 Posts: 73	I'd start with a PZ30. They're only $25, and easy to get. Your jet sizes depend on a variety of things, like exhaust system, air intake, elevation etc... If your bike ran fine before, just use a hacksaw, and saw off the bottom of the oem carburetor. Get a carburetor drill set, to measure the carburetor jet sizes. Then measure the jet sizes on the new carburetor. I've noticed that quite often the jet sizes built in the carburetor may say eg: 45 pilot, 110 main, but may actually be off by a few digits compared to a jet kit. Using a PZ30, allows you to get as close to OEM as possible. Some bikes have clearance issues with different carburetors. The benefits of a different carburetor are minimal, unless you really want to eke out the last MPH of top speed. Quite often carburetors like nibbi, Mikuni, or other, use different measurement units. So their jet sizes may differ from the PZ. They might also be larger in diameter than the PZ30 (which is exactly 30mm), which may help top end, but may make the bottom end (idle) suffer. I haven't yet found an in depth review about the differences in performance between all of them, but it's pretty unanimous. Larger mm carburetors run richer, and have better top end. Smaller carburetors run better MPG, and idle, at the expense of worse top end. And somewhere, your bike's engine can only take so much top end. So replacing a PZ30 with a Nibbi 30mm may, or may not get you more top end. Every brand is basically a different size. Size being the determining factor on top speed, or good idle. I see no reason not to go with a PZ, unless you really notice awful performance, which in most cases can be corrected with the correct jet sizes. __________________
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04-29-2024, 11:13 AM	#2
RubaSon Join Date: Apr 2024 Posts: 4	Hello, yes there are clearance issues with the PZ carb because of the long intake. The upper part of the carb hits the mount of the fueltank. With the shorter intake for the pwk it fits fine. I want to get rid of this split thing at the throtelcabel. So thats why i want to go with the PWK not to gain Power. The PZ runs good but not perfect. I tried different Jets the best i found was a 40 Pilot and 105 Main. I still mounted the PWK and startet with 38 pilot and a 120 Main but much to rich. Now i Test a 32 Pilot and 110 Main... I have tuned carbs before but only on 2 strokes thats why i need help because of the different behauvior.
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