Carburetor for a CCW

RubaSon · 04-28-2024, 05:55 AM

Hello , i am from germany and proud owner of a CCW Bobber 229cc.
Now i have trouble with my carburetor (PZ 30 with acceleration pump).
The pump did not work right now an the carb is a litle bit leaky. I want to replace the old carb and switch to an 30mm PWK. I need help with jetting so any recomendations would help. Thank you!

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.

GypsyR · 04-29-2024, 01:26 PM

No.1, why would you "hacksaw" the bottom of the carb off?
No.2. I like accelerator pumps. I wonder if a PZ30 might fit a Templar X? Looks a bit on the tall side, like a Keihin.

XLsior · 05-02-2024, 04:11 PM

Quote:

Originally Posted by GypsyR

No.1, why would you "hacksaw" the bottom of the carb off?
No.2. I like accelerator pumps. I wonder if a PZ30 might fit a Templar X? Looks a bit on the tall side, like a Keihin.

The PZ30 non pumper is a slimmer fit than a nibbi 28 and the throttle slide position is closer to the engine.

The main issue with the PZ30B pumper carb is its width increase due to the pumper diaphragm actuator...

The other main pain with the PZ30 is the under bowl position of the A/F screw which is a PITA...

ProDigit · 05-02-2024, 08:41 PM

Quote:

Originally Posted by XLsior

The PZ30 non pumper is a slimmer fit than a nibbi 28 and the throttle slide position is closer to the engine.

The main issue with the PZ30B pumper carb is its width increase due to the pumper diaphragm actuator...

The other main pain with the PZ30 is the under bowl position of the A/F screw which is a PITA...

If you buy them off of Amazon, the AF screw sits outside the hole by about 1/4th to 1/8th of an inch. On my Vader 150, I can easily adjust with a small flathead screwdriver.

...

And why would you hacksaw the bowl off? Because if you have a newer bike, you won't be able to create a slot in the screws, without damaging the (OEM carb) bowl anyway, in such a way that it would leak. They are 3 to 4 mm deep in the bowl.

TominMO · 04-29-2024, 05:49 PM

I am confused. None of my CCWs even have a carburetor.....

RubaSon · 04-30-2024, 05:36 PM

Mine has a carb...
I figured out how to choose the pilot jet but i dont know how to choose the right main jet?

RubaSon · 05-02-2024, 02:44 PM

I thougt it was the right pilot jet but it seem is it not. I tried different main jets from 120,115,110, 105 down to 100. I think 105 is good for now. Pilot ist acual a 32, idle is ok. If i close the throtle it comes quick to idle and stays there good but if i open the throtle quickly the engine dies. How can i know if its to rich or to lean?

XLsior · 05-02-2024, 04:06 PM

A quick diagnostic is to run the bike with the choke on...if it runs better/throttle response then the jetting is likely to lean.

when you play with pilot jetting then the A/F screw will need adjusting below 1/4 throttle range and idle.

after that you can play with needle position and main jet.

I'm no expert...been trying to adjust my nibbi carb for months after the 70mm big bore kit.

04-28-2024, 05:55 AM	#1
RubaSon Join Date: Apr 2024 Posts: 4	Carburetor for a CCW Hello , i am from germany and proud owner of a CCW Bobber 229cc. Now i have trouble with my carburetor (PZ 30 with acceleration pump). The pump did not work right now an the carb is a litle bit leaky. I want to replace the old carb and switch to an 30mm PWK. I need help with jetting so any recomendations would help. Thank you!
	0

04-28-2024, 08:53 PM	#2
ProDigit Join Date: Aug 2013 Location: FL Posts: 366	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. __________________
	0

04-29-2024, 05:49 PM	#7
TominMO Join Date: Sep 2021 Location: De Soto, MO Posts: 1,976	I am confused. None of my CCWs even have a carburetor..... __________________ 2021 Lifan Xpect--sold 2022 Lifan KPX 1972 Honda CT90--The Carrot 1969 Honda CT90--The Tomahto Cheesy is the WDK (workplace drama king). Now retired. Nope, back in the saddle. Nope, finally retired. Climate: The Movie https://www.youtube.com/watch?v=A24fWmNA6lM How our government really works https://www.youtube.com/watch?v=QjadCd0VRBw Question all authority.....think for yourself
	0

04-30-2024, 05:36 PM	#8
RubaSon Join Date: Apr 2024 Posts: 4	Mine has a carb... I figured out how to choose the pilot jet but i dont know how to choose the right main jet? Attached Thumbnails
	1

04-29-2024, 11:13 AM	#3
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.
	0

04-29-2024, 01:26 PM	#4
GypsyR Join Date: Feb 2023 Location: Upstate SC Posts: 339	No.1, why would you "hacksaw" the bottom of the carb off? No.2. I like accelerator pumps. I wonder if a PZ30 might fit a Templar X? Looks a bit on the tall side, like a Keihin.
	0

05-02-2024, 02:44 PM	#9
RubaSon Join Date: Apr 2024 Posts: 4	I thougt it was the right pilot jet but it seem is it not. I tried different main jets from 120,115,110, 105 down to 100. I think 105 is good for now. Pilot ist acual a 32, idle is ok. If i close the throtle it comes quick to idle and stays there good but if i open the throtle quickly the engine dies. How can i know if its to rich or to lean?
	0

05-02-2024, 04:06 PM	#10
XLsior Join Date: Aug 2020 Location: Australia Posts: 1,444	A quick diagnostic is to run the bike with the choke on...if it runs better/throttle response then the jetting is likely to lean. when you play with pilot jetting then the A/F screw will need adjusting below 1/4 throttle range and idle. after that you can play with needle position and main jet. I'm no expert...been trying to adjust my nibbi carb for months after the 70mm big bore kit.
	0