PWK 30mm or PZ30 pumper ?

[Red Hawk]

I’m gonna sacrifice the PZ30 in the Hawk to the Rhino 250 as it’s desperately needed. So I have an opening for an upgrade, the Hawk is ported and free flow exhaust. Can I get away with a 32mm PWK ? Or am I better off with a PZ30 pumper carb? I found the spigot adapter so I can dump the flange mount. But I lack the financial courage to just go buy everything and experiment.

Thanks all.

[Megadan]

With a ported head the 32mm will work, but you may suffer from some large carb side effects given that it is still on a stock cam. A 30mm PWK or PE would be a little more ideal. The PZ30 Pumper is a great upgrade for an otherwise stock motor, but from my own experience running one with my ported head, and then switching to the PE30 revealed just how restrictive the PZ30 was. The power and throttle response gains across the entire RPM range were dramatic.

Keep in mind that a PE and PWK 30mm are both smooth bore carbs while the PZ30 has a venturi, so it flows less air even though it is a "30mm" carb bore.

[JerryHawk250]

I would go with the pe30 on the ported Hawk head. The idle mixture and idle speed screw are on the right side of the carb and will be easier to access than the PKW30. They will perform about the same. I just ordered a pe30 for my new bike for when I port and deck it. The stock carb on the X22R is a pz30 pumper.

[Megadan]

Originally Posted by JerryHawk250

I would go with the pe30 on the ported Hawk head. The idle mixture and idle speed screw are on the right side of the carb and will be easier to access than the PKW30. They will perform about the same. I just ordered a pe30 for my new bike for when I port and deck it. The stock carb on the X22R is a pz30 pumper.

That is an excellent point that I completely forgot to mention. I absolutely love my PE30 for those reasons alone. The idle speed knob is also nice and big and easy to grab even with gloves on, so when I cold start it I can bump the idle up, and then reach down and lower it as the engine warms up. I carry a small flathead around to adjust the idle mixture as well when needed, also very easy to do even when sitting on the bike.

As seen here.

I would argue that the PWK will have a slight advantage in terms of throttle response and maybe even top end power due to the slide design creating a bit less turbulence, but it is probably so slight that most people would never know the difference.

You don't even need to buy the expensive Nibbi realistically, there are PE30's in the same price range as the PWK carbs that will likely be just fine. Example. https://www.aliexpress.com/item/3296...archweb201603_

[JerryHawk250]

This is the one I ordered. I have a choke Lever on the handle bar is the only reason I choose this one over the Nibbi.
https://www.amazon.com/dp/B084FSC6ZJ..._vYWyEbEN35018

[Red Hawk]

Thanks for all the info Dan & Jerry, I found an intake adapter on Amazon. Will this work for the PE30?

https://www.amazon.com/dp/B07PCMS2YG...A3DKJ52P82LHDI

[Megadan]

Originally Posted by JerryHawk250

This is the one I ordered. I have a choke Lever on the handle bar.
https://www.amazon.com/dp/B084FSC6ZJ..._vYWyEbEN35018

That one has something that I have noticed is common with the cheaper PE30 carbs, which is that hose barb fitting on the back side of the carb. It will need to be blocked with a vacuum cap if it is open to the atmosphere to the bore of the carb or it will be one heck of a vacuum leak. The Nibbi has that part of the casting close off. No idea why they do it, nor is it a big deal, just something I noticed.

[NzBrakelathes]

PE28 with flange like stock.....
Thoughts?!

[China Rider 27]

Originally Posted by NzBrakelathes

PE28 with flange like stock.....
Thoughts?!

Interesting. If it uses standard HAWK spacing and it would do away with the expense of a separate manifold. Does it come in 30 mm? Might be a good setup on a stock bike. Getting the idle mixture screw on the side would be a game changer for tuning no doubt!

[Megadan]

Originally Posted by Red Hawk

Thanks for all the info Dan & Jerry, I found an intake adapter on Amazon. Will this work for the PE30?

https://www.amazon.com/dp/B07PCMS2YG...A3DKJ52P82LHDI

No, for the reason Jeffery pointed out.

This is the style that Jerry used on his Hawk and it worked. https://www.aliexpress.com/item/1886...09239-VnYZvQVf

I tried using that on my Hawk, but due to a difference in the frame construction of my 2018 vs. his 2016, the carb hit part of the frame on my bike.

After spending more on carb adapters than I did on carburetors (not joking). I finally stumbled across this one one Taobao, which after shipping to the U.S. worked out to be about 12 bucks in total. It was the ONLY intake I found that allowed the carb to clear the frame. https://item.taobao.com/item.htm?spm...ucket=2#detail

The downside is that it sets the carb further back and the throttle cable then becomes a small issue with clearance to the tank, ideally requiring an angled metal guide end on the cable at the carb cap.

In short, hope that you don't need to do what I did lol

[Savageman69]

Well damn after I read megadans post I had to google the difference between smooth bore and an Venturi style carburetor. Learn all kinds of stuff on this forum just browsing. I'd say I bet the smooth bore makes a huge difference

[Megadan]

Originally Posted by Savageman69

I'd say I bet the smooth bore makes a huge difference

Even with no change to the bore size it can mean a large increase in airflow, but more importantly, there is no reduction in charge velocity created by the bottle neck of the standard venturi shape. This means an increase in both throttle response as well as total airflow.

That being said, the standard PZ30 style carb on an otherwise unmodified engine is way more than sufficient. My first Hawk had no head portong and a VM26 clone with just basic bolt on mods and it could still manage to hit close to 70mph with 17/43 sprockets. The only real difference between that bike and my current one is the acceleration as my top speed is more or less limited by the gearing in relation to the power curve. That was a personal choice since these bikes at anything over 65 mph start to get a bit sketchy feeling.

[NzBrakelathes]

This PE28 was intended to replace the PZ but needs a wee step adaptor at the back where it mounts to air box
Still would seem easier upgrade but I’ve not tried as I’ve not got an air cooled cord china bike

[China Rider 27]

Before we all go out and retire our PZ30, 30B, Mikuni in favor of the smooth bore we should consider what we are trying to achieve. Stands to reason that a PE28 or PE30 or PWK30 could be adjusted to run well on a stock engine AND you get the prize of side idle mixture adjustment which alone may justify its use provided the overall function is good. Top speed aside, then seems we are talking about the best acceleration between the carburetors and low speed torque and drive ability. Another consideration would be fuel mileage in relation to performance increase. As far as a stock motor, until we have evidence of how a smooth bore works on a stock engine we have not really established if there is substantial improvement to justify its use. And then how easy is it to tune a PE30 or PWK30?

[Megadan]

Originally Posted by China Rider 27

Before we all go out and retire our PZ30, 30B, Mikuni in favor of the smooth bore we should consider what we are trying to achieve. Stands to reason that a PE28 or PE30 or PWK30 could be adjusted to run well on a stock engine AND you get the prize of side idle mixture adjustment which alone may justify its use provided the overall function is good. Top speed aside, then seems we are talking about the best acceleration between the carburetors and low speed torque and drive ability. Another consideration would be fuel mileage in relation to performance increase. As far as a stock motor, until we have evidence of how a smooth bore works on a stock engine we have not really established if there is substantial improvement to justify its use. And then how easy is it to tune a PE30 or PWK30?

I don't forsee too many people going out and retiring their PZ/VM carbs for a PE setup. There are upsides as you pointed out, but there are also some hurdles to the change as well, namely the intake side of things. Airbox AND engine.

Also, as you pointed out, and something I have tried to establish, this entire discussion has been between people that have ported cylinder heads and other modifications.

As far as fuel economy, if the engine is otherwise unchanged between the two carbs, the economy will be just about the same. My PZ30B and my PE30 both get right around 55-60mpg if I can manage to keep out of the throttle lol.

Jetting setup on the PE30 is just as easy as the PZ30, and in some ways easier.