The PZ30B "Pumper" thread.

[Megadan]

Just decided to throw something together for anybody that is considering this carb, but has never dealt with one like it before. If you are considering a Mikuni clone, then I invite you to a great alternative with some performance benefits for any of your throttle twisters out there.

The Carburetor in question is known, as the title suggests, as a PZ30B. Often listed as a PZ30 Accelerator Pump carb on websites like Aliexpress and ebay. In this video I explain the main differences between this carb and the standard one as well as how to do the basic setup on it.




As I mentioned in the video the nozzle for the accelerator pump should be aimed down the middle of the carburetor for proper function. If you test yours and you find that it doesn't, and like mine was spraying the side of the carburetor bore (blue line in pic). You will need to adjust it so that it is similar to the green line.


How you would do that is start by removing the bowl of the carburetor, and then using something soft (a bit of wood or plastic) you will want to pry or tap out the jet. Just be careful not to bend it. Go as gently as you can and apply even pressure. It should eventually pop out.

Once the nozzle is out you will see a notch on one section on the bottom of the jet (yellow arrow). This notch is there to denote what direction the jet is spraying. Simply turn it so that it faces the back of the carb at your desired direction and then press it back in with an appropriate bit of rod or a small roll pin punch. If you want to test the spray pattern before putting the bowl back on, I find that a can of carb cleaner with a straw on it works well by spraying up through the bottom of the nozzle, and its a good way to ensure it is clean.


One other thing you may run into with your pumper carb is that the throttle cam for the accelerator pump has a bit of play in it and may bind up or cause the throttle to get stiff. If yours does this, a thrust washer big enough to sit on all sides of the cam between it and the bracket is a great way to solve the issue for cheap. It will also ensure that the throttle cam returns and hits the stop on the carb body.





The great thing is, with this carburetor you can simply use the same jetting you may be running on the stock style carburetor and transfer it over. It is possible to get two different styles of pilot jets, but the same sizes will translate over between the styles. The difference in how the bike rides/feels is pretty awesome, and hard to describe. Awesome is a good word for it.

[OneLeggedRider]

Very impressive Dan and thorough as always. Would this be a Keihin clone? And can you elaborate on the different pilot jet styles? And would this affect your needle clip setting? And lastly can we know what size jets you're running with your modded head? Enquiring minds want to know lol.

[Megadan]

Originally Posted by OneLeggedRider

Very impressive Dan and thorough as always. Would this be a Keihin clone? And can you elaborate on the different pilot jet styles? And would this affect your needle clip setting? And lastly can we know what size jets you're running with your modded head? Enquiring minds want to know lol.

Yes, this is technically a Keihin clone. There are some goofy exceptions since these are made in China though. Mine is a GREAT example of that. The carb says Mikuni on the body, but uses the Keihin PZ30 bowl. It runs Mikuni main jets, and a Hawk style pilot jet. (Confused yet?)

Most of them tend to run Keihin jets. Like this one: https://www.aliexpress.com/item/KEIH...9-fe9737708a69
Main jet 99101-393
Pilot jet N424-21

While I am normally an advocate for genuine jets, this kit would be a great way to get dialed in if you have one using those jets. https://www.amazon.com/QUIOSS-Carbur...VHS2P6X5MFC282

As far as adjusting the jetting, that depends. As a whole, I would say there is no real changes in jetting needed if you were to go from a stock carb to this one. The one exception to this would be if you are running one or more jet very rich already. In that instance, backing it off a hair and leaning it out would be a good idea to prevent potential bogging.

As far as my jetting. I am running a Mikuni N100.604 125 main jet. Needle in the middle(3rd) notch, and a "45" sized Hawk style pilot jet.

[China Rider 27]

Ah yaa! Sign me up for class! The conversation the past few days about building on the stock carb with the PZ30B got me excited as I realized something sorely needed may start soon to be developed. I have thought the PZ30B the logical carb upgrade since I first started understanding HAWK carburetion some 3 months ago. In fact I sent a PZ30B back yesterday because it had some weird pilot jet I was unable to cross reference on Jets R Us. I ordered another one. The whole lay out from stock carb upgrade to PZ30B progression with parts descriptions and tuning tips is sorely needed. Hats off to Megadan, Hawk guru, for stepping up!

[Megadan]

Originally Posted by China Rider 27

Ah yaa! Sign me up for class! The conversation the past few days about building on the stock carb with the PZ30B got me excited as I realized something sorely needed may start soon to be developed. I have thought the PZ30B the logical carb upgrade since I first started understanding HAWK carburetion some 3 months ago. In fact I sent a PZ30B back yesterday because it had some weird pilot jet I was unable to cross reference on Jets R Us. I ordered another one. The whole lay out from stock carb upgrade to PZ30B progression with parts descriptions and tuning tips is sorely needed. Hats off to Megadan, Hawk guru, for stepping up!

Thank you. We had a thread a while back discussing the pumper carb, but only two or three of us made the leap at that time and it wasn't really discussed further.

In my opinion, short of a PWK/OKO or PE 28 or 30mm smooth bore carb, this is the only real "upgrade" in terms of any performance benefit. The Mikuni is a great upgrade in terms of tuning capability, but otherwise doesn't offer any real performance increase.

The problem you ran into is honestly the one draw back. I ran into the same thing when I ordered mine, but by happy circumstance it used the same pilot jet as the Hawk. The one downside to that is that there are no real options for a new pilot jet - hopefully that will change with NzBrakeLathe's discovery of said jets in different sizes. The one I posted, and a couple others on Aliexpress, come with rebuild kits and a couple of extra jets, which actually lets you see what type of jets they use. The only ones I would buy would be those, just to ensure I am getting something that has jetting options.

The quarter turn throttle is honestly a nice and welcome upgrade to the stock throttle as well, which requires one heck of a range of motion to go from idle to wide open lol.

EDITL I also realized I was missing a picture and updated the first post to include it. Oooops

[OneLeggedRider]

I like seeing the stream of fuel shoot right down the middle of the carb right under the slide as it's going up, that's pretty slick. Puts me in mind of my 800cfm Q-jet. But even if it hit the side of the venturi it would probably net about the same results (I know most of us would be a little wary of tapping that jet out to align it). I'm also interested in the quick twist throttle. Mine seems to have quite a bit of play even after adjusting it.

[Megadan]

Originally Posted by OneLeggedRider

I like seeing the stream of fuel shoot right down the middle of the carb right under the slide as it's going up, that's pretty slick. Puts me in mind of my 800cfm Q-jet. But even if it hit the side of the venturi it would probably net about the same results (I know most of us would be a little wary of tapping that jet out to align it). I'm also interested in the quick twist throttle. Mine seems to have quite a bit of play even after adjusting it.

Eh, its a pretty sturdy little nozzle, and it didn't take a ton of force to get out, the bottom is just a small knurled end that seats it in the hole, which has a slight taper. It literally presses in and out with light human power. No hammer required. Every single jet on a GL1000 carburetor (all 6 of them x 4 carbs) are press fit, so it's nothing new to me

The quick twist throttle with the new cable adjusts out to a lot less free play than the stock stuff. I have maybe 4 or 5mm of throttle free play at the bars, and it can actually be adjusted too far and have the throttle open when the bars turn. There isn't a ton of adjustment range left at that point, but it at least has some. The stock cable on mine was maxed out and the throttle still had like half an inch of play to it. Drove me nuts.

The nice thing is, these cables can be found on amazon and ebay for about 10-12 bucks each. I have a couple of backups on hand after my first cable broke at the throttle. So of course, this one will probably never break lol.

[China Rider 27]

The pilot jet is the holy grail I fear. My HAWK runs pretty good under throttle but the idle wanders considerably at different times and rather than put more money into it without a known solution getting an accurate and adjustable pilot jet is key. So the move to PZ30B has to have replaceable pilot jets. Now the Magician I got few weeks ago runs great with only slight idle speed adjustments. Starts with no choke or throttle engagement and idles. I hit 60 mph with it and probably has some more in it. Don't know what's in that carb but one day I am going to find out. I ordered a stand alone carb like the one you show a link to. Hopefully it has a Keihin pilot jet.

[Megadan]

Originally Posted by China Rider 27

The pilot jet is the holy grail I fear. My HAWK runs pretty good under throttle but the idle wanders considerably at different times and rather than put more money into it without a known solution getting an accurate and adjustable pilot jet is key. So the move to PZ30B has to have replaceable pilot jets. Now the Magician I got few weeks ago runs great with only slight idle speed adjustments. Starts with no choke or throttle engagement and idles. I hit 60 mph with it and probably has some more in it. Don't know what's in that carb but one day I am going to find out. I ordered a stand alone carb like the one you show a link to. Hopefully it has a Keihin pilot jet.

If the one you ordered is from the same store, then you should be good to go. The other two people that ordered one around the time I ordered this one bought that exact carb and it takes normal pilot jets.

This is ChondaChondaChonda's post from the older thread, he ordered the exact kit I linked, and this is some very good shots of the carb and the jets. The YOU-ALL cast into the body always gives me a giggle.
http://chinariders.net/showpost.php?...5&postcount=13

As far as the stock carb and the idle issues. I honestly think it is actually a design flaw in the pilot jet itself that causes it. Even my pumper, which uses that same style jet, has a tempermental idle sometimes. Even in the same conditions on the same day. I would almost wager it has to do with the fact that the main body of the carb that sits in the bowl leaks a little fuel or air past the outside of the pilot jet. Traditional pilots screw into that location, so the threads somewhat seal it off, but since the Hawk threads it at the very top it has to rely on the two surfaces seating against each other, and I think they just don't seal well enough. This is probably why the Mikuni is so easy to get dialed in, and why the TT250 and other bikes that use a PZ30 with more traditional pilot jets don't have the same issues as the Hawk.

If I were going to do this all from scratch, I would order that carb kit and (enjoy the free grips lol) nand the jet kit I linked from Amazon. Sure, it's $57 all said and done, but you are getting a good number of upgrades from stock for your money. Quick turn throttle with a CNC housing and thick plastic throttle tube which is quite nice I might add, the pumper carb itself, and some nice grips which are bound to be better than the stock Hawk grips... anything is better than those things.

[JerryHawk250]

Here is a link to the pumper carb with the standard pilot jet. https://www.aliexpress.com/store/pro...126818dfQW6dUu

[Megadan]

Originally Posted by JerryHawk250

Here is a link to the pumper carb with the standard pilot jet. https://www.aliexpress.com/store/pro...126818dfQW6dUu

That's the same one I linked above.

Here is the one I bought, so if you want to avoid dealing with Hawk style goofy pilot jets, do NOT buy this one. https://www.aliexpress.com/item/KEIH...27424c4dfogb5j


This is the one that Weldandgrind bought, and as far as I know it uses the same Keihin pilot jets as the Powerzone one. No throttle with this one, but that's easy enough to find. https://www.ebay.com/itm/26342240991...&ul_noapp=true

[China Rider 27]

I agree YOU ALL! The ali-express combined kit looks to be the way to go and I tried to order it couple months ago using my credit card and aborted it in hesitation, however they got my credit card info and immediately charged fradulent charges requiring I cancel my card. The only way to purchase on this site securely seems to be by Western Union wire transfer that I can figure out. What am I missing about ordering securely from Ali-express?

The carb package is listed on ebay at $59.00 and stand alone for $42.00.

Just to have all the options here is the link.

https://www.ebay.com.au/itm/PZ30-30m...AAAOSwGIZcCU88

And $59.00

https://www.ebay.com.au/itm/PowerZon...IAAOSwtjhb9TOn

I was not going to spend the extra $20.00 but it was tempting!

[JerryHawk250]

I've ordered a few items from Aliexpress using my credit card with no issues. On the other hand it's worth the extra money to be protected my Ebay and use paypal for extra protection. Personally I would save the $20 and get it without the throttle.

[China Rider 27]

I am getting excited now, I hope I get a YOU All casting. I would pay $5 extra for it! I think we should start a YOU All club! Second thought, maybe should wait and see how it runs.

[Megadan]

Alternative ebay route.

Carb with cable and "rebuild kit" https://www.ebay.com/itm/26342240991...&ul_noapp=true

Throttle assembly. https://www.ebay.com/itm/7-8-22mm-Qu...MAAOSwGtRXxXZ5

Those combined are about 48 bucks.

Fancier all aluminum throttle assembly if you are feeling a bit more spendy. https://www.ebay.com/itm/7-8-22mm-Qu...MAAOSwGtRXxXZ5

The throttles are from US sources with "fast n free" shipping. You can get them from a Chinese source for a few bucks less if you don't mind waiting.