The PZ30B "Pumper" thread. - Page 5

Cravin01 · 07-07-2019, 02:09 AM

Compare to my carburetor, I filled it with gas off the bike in there somewhere and showed the stream. It put out just as much hooked up to the bike.

Good luck and sorry about the headache but it's all worth it in the end!

Megadan · 07-07-2019, 03:12 AM

I am pretty sure I know where your problem is, but bear with me as I run through the accelerator pump design and parts just so other people have it as a reference.

So in this first picture, after removing the lower bowl from the accelerator pump and getting the spring out of the way we have this view. The bowl is flipped over to the right to mirror its flange as it mates to it. The diaphragm has a seal that also seals off two small ports (arrows). The yellow arrow is the feed directly from the bottom of the main bowl through a small passage that ends in a small brass jet in the center of the accelerator pump bowl. Behind this is a check valve that prevents the fuel from back feeding into the main bowl, but also releases when the diaphragm retracts to pull in more fuel. The green arrow is the main passage that feeds up to the nozzle.

For reference purposes, here is how the plunger, diaphragm, spring, and pumper bowl are assembled in order.

Moving on the the nozzle end of the circuit at the flange side of the main bowl there is an O ring seal, a small brass jet with a spring, and a tiny ball bearing that act as a check valve to keep fuel in the nozzle ready to be fired into the throat of the carburetor. These screw in where my thumb is located and install in the order they are laid out from left to right.

This leads me to where I think your problem is. Obviously we are getting fuel into the accelerator pump bowl, so I will assume that the feed from the main bowl and that check valve are functioning properly.

I believe the issue is with the check valve on the nozzle end. If that brass jet with the spring is screwed down too far it will not allow fuel to go by, or very little, because the ball can either not move, or the spring pressure is too high for it to pump past. This jet (blue arrow) should be just about flush, or slightly below the level of, the main bowl flange. An easy way to check this is to blow through from the bottom of that passage where the accelerator pump feeds up. You should be able to blow air through relatively easily (given how small the passage is).

If you check this, adjust it if needed, and still don't get any fuel to come out of the nozzle, then my next stop would be to make sure the check valve in the accelerator pump bowl that leads to the main bowl feed is functioning properly. It is possible that this is not sealing properly - either the ball bearing is missing or maybe it is jammed into the spring - and you just are not building enough pressure and the fuel is bleeding back out into the bowl.

duck9191 · 07-07-2019, 06:09 PM

I think your right, one thing I noticed while cleaning the bowl is that if you depresse the pumper plunger while the bowl was off, the gas would shoot out of the feed hole in the bottom of the bowl, not the port to the jet in the throat.

It will work as intended if you quickly depress the plunger all the way, but that is a lot more travel then you would ever get from the action of the cam.

I think the check valve is cranked in there well below flush. I'll check in a bit.

duck9191 · 07-07-2019, 07:42 PM

So I loosened the check valve on the output side and it didn't seem to help, most of the fuel goes back into the bowl. So I checked the check valve in the accelerater pump bowl and it looked good. I flushed it out and put it back together and it's still back feeding into the bowl. Maybe there is a machining defect or something.

As you can see, if you quickly fully depress the plunger it will shoot gas out the output but it's still back feeding.

NzBrakelathes · 07-07-2019, 09:22 PM

Quote:

Originally Posted by duck9191

So I loosened the check valve on the output side and it didn't seem to help, most of the fuel goes back into the bowl. So I checked the check valve in the accelerater pump bowl and it looked good. I flushed it out and put it back together and it's still back feeding into the bowl. Maybe there is a machining defect or something.

As you can see, if you quickly fully depress the plunger it will shoot gas out the output but it's still back feeding.

Can you check both check valve to see if they hve ball then tiny spring then the orifice?
That is both inside plunger and in the bowl.

Also you have a spring under the plunger to base?

duck9191 · 07-07-2019, 09:58 PM

I checked both of the check valves, they where all free.

NzBrakelathes · 07-08-2019, 01:29 AM

Quote:

Originally Posted by duck9191

I checked both of the check valves, they where all free.

So ball goes in then the tiny spring the the jet/hole thingy?
Also when you have the cable wheel thingy cranked all the way around can you push the plunger in just a little further or a lot further?

I just check mine and when say FULL THROTTLE I could only press the plunger in by hand a little but more say 2-3mm

duck9191 · 07-08-2019, 07:24 AM

Yes they are assembled correctly.

You can see how far the cam is moving the plunger in the previous video. It's rotating to the max throw.

Megadan · 07-08-2019, 10:23 AM

Quote:

Originally Posted by duck9191

So I loosened the check valve on the output side and it didn't seem to help, most of the fuel goes back into the bowl. So I checked the check valve in the accelerater pump bowl and it looked good. I flushed it out and put it back together and it's still back feeding into the bowl. Maybe there is a machining defect or something.

As you can see, if you quickly fully depress the plunger it will shoot gas out the output but it's still back feeding.

The check valve orifice/jet for the nozzle is still turned in too far both in the video and in the picture below it. That needs to be backed out until the top surface of it is nearly even with the bowl flange as I mentioned previously. In the video and picture it is too tight/screwed in way too far. The inside of the O ring should actually be touching it. Compare my last picture to your first one and note the difference. That is all it takes to create too much spring tension on the check ball and cause the pressure needed to bypass it to be incredibly high.

duck9191 · 07-08-2019, 10:31 AM

I'll try that, it was way further down then that to start.

duck9191 · 07-08-2019, 10:41 PM

With the jet above flush with the face of the bowl it seems to work, just under flush it starts to backfeed into the bowl. Gonna knock some off the head of the jet so I can leave it backed out that little bit extra.

Next step is jetting it for my stock bike. Tried 40/108 2.5 turns out and it idled fine but would bog with any throttle over 1/4. The needle was at 3rd down. Might drop back to the 105 and second slot, not sure if I have anything between the stock 35 and the 40.

Has anyone found a decent af screw that's knurled or at least long enough to adjust with your finger? I have saw them on ebay but reviews are less then promising lol.

NzBrakelathes · 07-08-2019, 11:24 PM

Quote:

Originally Posted by duck9191

With the jet above flush with the face of the bowl it seems to work, just under flush it starts to backfeed into the bowl. Gonna knock some off the head of the jet so I can leave it backed out that little bit extra.

Next step is jetting it for my stock bike. Tried 40/108 2.5 turns out and it idled fine but would bog with any throttle over 1/4. The needle was at 3rd down. Might drop back to the 105 and second slot, not sure if I have anything between the stock 35 and the 40.

Has anyone found a decent af screw that's knurled or at least long enough to adjust with your finger? I have saw them on ebay but reviews are less then promising lol.

Glad you found the issue

This tool will help you
https://www.ebay.com/itm/303210660601

franque · 07-08-2019, 11:57 PM

I've got one of these, you might be able to get it quicker:

https://www.amazon.com/Motion-Pro-08.../dp/B000UKD6YC

duck9191 · 07-09-2019, 02:11 PM

I am looking for something more like this.

https://smile.amazon.com/Motorcycle-...3EJRP1AE49KKPT

NzBrakelathes · 07-09-2019, 11:19 PM

Quote:

Originally Posted by duck9191

I am looking for something more like this.

https://smile.amazon.com/Motorcycle-...3EJRP1AE49KKPT

Can be made you got big money to invest?
Also I suspect they may vibrate loose etc.
Better off with the other proper tool.

07-07-2019, 02:09 AM	#61
Cravin01 Join Date: Jan 2018 Location: Forney Texas Posts: 498	Compare to my carburetor, I filled it with gas off the bike in there somewhere and showed the stream. It put out just as much hooked up to the bike. Good luck and sorry about the headache but it's all worth it in the end! __________________ Visit me on YouTube at "Project Next"! https://www.youtube.com/channel/UC6KTCi2GVbfRDv-2XCqHhsg?view_as=subscriber 2017 Bashan Storm Keihen PZ30 Pumper Carb,115 main jet,35 pilot jet, gutted factory exhaust, Sambo Digital Speedometer,LED blinkers, H4 headlight,D.I.D X-ring chain 428,17/42 sprockets,UNI cone filter.
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07-07-2019, 03:12 AM	#62
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,034	I am pretty sure I know where your problem is, but bear with me as I run through the accelerator pump design and parts just so other people have it as a reference. So in this first picture, after removing the lower bowl from the accelerator pump and getting the spring out of the way we have this view. The bowl is flipped over to the right to mirror its flange as it mates to it. The diaphragm has a seal that also seals off two small ports (arrows). The yellow arrow is the feed directly from the bottom of the main bowl through a small passage that ends in a small brass jet in the center of the accelerator pump bowl. Behind this is a check valve that prevents the fuel from back feeding into the main bowl, but also releases when the diaphragm retracts to pull in more fuel. The green arrow is the main passage that feeds up to the nozzle. For reference purposes, here is how the plunger, diaphragm, spring, and pumper bowl are assembled in order. Moving on the the nozzle end of the circuit at the flange side of the main bowl there is an O ring seal, a small brass jet with a spring, and a tiny ball bearing that act as a check valve to keep fuel in the nozzle ready to be fired into the throat of the carburetor. These screw in where my thumb is located and install in the order they are laid out from left to right. This leads me to where I think your problem is. Obviously we are getting fuel into the accelerator pump bowl, so I will assume that the feed from the main bowl and that check valve are functioning properly. I believe the issue is with the check valve on the nozzle end. If that brass jet with the spring is screwed down too far it will not allow fuel to go by, or very little, because the ball can either not move, or the spring pressure is too high for it to pump past. This jet (blue arrow) should be just about flush, or slightly below the level of, the main bowl flange. An easy way to check this is to blow through from the bottom of that passage where the accelerator pump feeds up. You should be able to blow air through relatively easily (given how small the passage is). If you check this, adjust it if needed, and still don't get any fuel to come out of the nozzle, then my next stop would be to make sure the check valve in the accelerator pump bowl that leads to the main bowl feed is functioning properly. It is possible that this is not sealing properly - either the ball bearing is missing or maybe it is jammed into the spring - and you just are not building enough pressure and the fuel is bleeding back out into the bowl. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	1

07-07-2019, 06:09 PM	#63
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	I think your right, one thing I noticed while cleaning the bowl is that if you depresse the pumper plunger while the bowl was off, the gas would shoot out of the feed hole in the bottom of the bowl, not the port to the jet in the throat. It will work as intended if you quickly depress the plunger all the way, but that is a lot more travel then you would ever get from the action of the cam. I think the check valve is cranked in there well below flush. I'll check in a bit. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
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07-07-2019, 09:58 PM	#66
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	I checked both of the check valves, they where all free. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
	0

07-08-2019, 07:24 AM	#68
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	Yes they are assembled correctly. You can see how far the cam is moving the plunger in the previous video. It's rotating to the max throw. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
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07-08-2019, 10:31 AM	#70
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	I'll try that, it was way further down then that to start. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
	0

07-08-2019, 10:41 PM	#71
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	With the jet above flush with the face of the bowl it seems to work, just under flush it starts to backfeed into the bowl. Gonna knock some off the head of the jet so I can leave it backed out that little bit extra. Next step is jetting it for my stock bike. Tried 40/108 2.5 turns out and it idled fine but would bog with any throttle over 1/4. The needle was at 3rd down. Might drop back to the 105 and second slot, not sure if I have anything between the stock 35 and the 40. Has anyone found a decent af screw that's knurled or at least long enough to adjust with your finger? I have saw them on ebay but reviews are less then promising lol. __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
	0

07-08-2019, 11:57 PM	#73
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	I've got one of these, you might be able to get it quicker: https://www.amazon.com/Motion-Pro-08.../dp/B000UKD6YC
	0

07-09-2019, 02:11 PM	#74
duck9191 Join Date: May 2019 Location: Port Huron, Michigan Posts: 637	I am looking for something more like this. https://smile.amazon.com/Motorcycle-...3EJRP1AE49KKPT __________________ 2020 Triumph Tiger 900 rally. 2018 Bashan Storm 250. pz30b, digital cluster + gear indicator, unifilter and car customs full exhaust. 2019 Taotao 110b boulder atv. The "arm breaker" lol 2007 Honda VTX 1300R. 1974 Suzuki tm125, work in progress 2001 Suzuki Drz 400s.
	0