Zongshen 125 - What Carb

Sport Rider · 05-14-2018, 08:49 PM

grandson's bike will NOT run right. stock carb is a PITA to try to get into. Figured I would go the same direction and put another carb on it. Can someone suggest the correct one for it?

on the side of the carb is PZ26.

and if you have any jet suggestions, that would help too.

Thanks in advance!

Douglass · 05-15-2018, 01:04 AM

I installed a Mikuni VM22 (26mm) carb in my Apollo RFZ db-x18 125cc. I am at sea level, and installed a 20 pilot, with a 112.5 main, needle clip in the forth slot down from the top. My air screw is 1 1/4 turns out from closed. If you are around 800 to 1000 ft from sea level, you might be able to use the stock pilot jet which I believe is a 15, and install 110 main jet. My Mikuni came with a 15 pilot, and a 95 main. You could try it out of the box, and get difference jets later too if needed. The Mikuni looks a little different than what the stock one looks like, but it is a very nice carb, and the bike runs real good. The Mikuni also bolted right up, no mods needed. I could not get a good constant idle with the stock carb (my stock carb looks the same as the one in your picture), but now the engine idles for days. I drove the hell out of it on Saturday.

https://www.amazon.com/MIKUNI-VM22-C...uni+vm22&psc=1

Sport Rider · 05-20-2018, 02:51 PM

got the parts yesterday. I got an assortement set of mains from 86 to 110. I put the 100 in for now. I got a 15 pilot, but it was the wrong style. had to order a 17.5. I put the main in with the pilot which came with the bike. bike started up on 3 kicks and I adjusted the idle a bit. ran fine except on high rpms where it stumbled, likely from fuel starvation. I'll adjust the float level and see if that fixes it.

Once I get the other pilot in, I'll tune it a bit better, but for now it's running MUCH better!

Douglass · 05-20-2018, 06:01 PM

.

Quote:

I'll adjust the float level and see if that fixes it.

It might be a good idea to install the 110 main jet before messing with the float. If it still has a slight bog try rasing the needle, by lower the clip one postion. I bet once you cahnge the main jet, you'll be in good shape.

Quote:

Once I get the other pilot in, I'll tune it a bit better, but for now it's running MUCH better!

Glad to hear it improved the bike.

Sport Rider · 05-28-2018, 10:31 AM

installed the 17.5 pilot over the weekend. runs better now, even at higher RPMs where I seemed to get a bit of fuel starvation/stumble. Ready for the grandson to learn how to use a clutch!

Douglass · 05-29-2018, 11:41 AM

Did you change the main jet too or just the pilot?

Sport Rider · 05-29-2018, 12:03 PM

Quote:

Originally Posted by Douglass

Did you change the main jet too or just the pilot?

100 main for now. I may try a 105 later on. will have to check the plug and tune from where I am now.

05-15-2018, 01:04 AM	#2
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	I installed a Mikuni VM22 (26mm) carb in my Apollo RFZ db-x18 125cc. I am at sea level, and installed a 20 pilot, with a 112.5 main, needle clip in the forth slot down from the top. My air screw is 1 1/4 turns out from closed. If you are around 800 to 1000 ft from sea level, you might be able to use the stock pilot jet which I believe is a 15, and install 110 main jet. My Mikuni came with a 15 pilot, and a 95 main. You could try it out of the box, and get difference jets later too if needed. The Mikuni looks a little different than what the stock one looks like, but it is a very nice carb, and the bike runs real good. The Mikuni also bolted right up, no mods needed. I could not get a good constant idle with the stock carb (my stock carb looks the same as the one in your picture), but now the engine idles for days. I drove the hell out of it on Saturday. https://www.amazon.com/MIKUNI-VM22-C...uni+vm22&psc=1
	2

05-20-2018, 02:51 PM	#3
Sport Rider Join Date: Jan 2016 Location: Mooresville NC Posts: 2,041	got the parts yesterday. I got an assortement set of mains from 86 to 110. I put the 100 in for now. I got a 15 pilot, but it was the wrong style. had to order a 17.5. I put the main in with the pilot which came with the bike. bike started up on 3 kicks and I adjusted the idle a bit. ran fine except on high rpms where it stumbled, likely from fuel starvation. I'll adjust the float level and see if that fixes it. Once I get the other pilot in, I'll tune it a bit better, but for now it's running MUCH better!
	1

05-28-2018, 10:31 AM	#5
Sport Rider Join Date: Jan 2016 Location: Mooresville NC Posts: 2,041	installed the 17.5 pilot over the weekend. runs better now, even at higher RPMs where I seemed to get a bit of fuel starvation/stumble. Ready for the grandson to learn how to use a clutch!
	1

05-29-2018, 11:41 AM	#6
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	Did you change the main jet too or just the pilot?
	0