Carburetor frustrations

noah9988

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I'm getting fed up with carburetor trouble. Most recently I've tried a pz22, and the pilot jet that came with it was too big, so I needed to order some... except they only ship from china. After receiving them I realized that the stock jet is a 30 and the smallest one I have is a 30, but they don't make ones smaller than 30... Other than the pilot jet issue it runs and works well. EXCEPT the bowl o ring somehow expanded and will not fit in the groove anymore. I tried making my own with gasket material, but it leaks. I've tried going back to my bofeng/speed carb but they both have air leaks, and I need to get an o ring for the intake side.

My main gripe is trying to figure out if a carb will have a pilot jet that I can actually swap out and get it to run correctly.

Anyone have carb recommendations?
 

DAMIEN1307

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I've tried going back to my bofeng/speed carb but they both have air leaks, and I need to get an o ring for the intake side.
Then I would get the O ring from an autoparts store for the BoFeng and use that...Mine runs flawlessly with the BoFeng with plenty of smooth power and speed in all throttle ranges.
 

noah9988

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Then I would get the O ring from an autoparts store for the BoFeng and use that...Mine runs flawlessly with the BoFeng with plenty of smooth power and speed in all throttle ranges.
Probably the best idea tbh, and it won't cost me a lot of money lol. I am interested in the bbr tuning oko carb but I'm not sure if I can hook it up to my setup.
 

ImpulseRocket89

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I'm getting fed up with carburetor trouble. Most recently I've tried a pz22, and the pilot jet that came with it was too big, so I needed to order some... except they only ship from china. After receiving them I realized that the stock jet is a 30 and the smallest one I have is a 30, but they don't make ones smaller than 30... Other than the pilot jet issue it runs and works well. EXCEPT the bowl o ring somehow expanded and will not fit in the groove anymore. I tried making my own with gasket material, but it leaks. I've tried going back to my bofeng/speed carb but they both have air leaks, and I need to get an o ring for the intake side.

My main gripe is trying to figure out if a carb will have a pilot jet that I can actually swap out and get it to run correctly.

Anyone have carb recommendations?
Just out of curiosity, why have you determined the pilot is too big? A 30 in Keihin sizing is .30mm or .0118in. Keihin never even offered pilot jets in that style below a 35, anything smaller than that will be an aftermarket sizing. A 30 is pretty dang small. If you think you have the skill you could solder and drill down with an 87 drill bit, which is .25mm - a "25" jet. It's definitely not easy to do when you get into bits that small though.

Have you checked the float height? For a PZ carb it should be set to 22mm (.866") and have 24mm of drop. Too high of a float can cause a small amount of extra fuel to be pulled under vacuum, which can make you chase your tail trying to get a tune figured out.
 

noah9988

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Just out of curiosity, why have you determined the pilot is too big? A 30 in Keihin sizing is .30mm or .0118in. Keihin never even offered pilot jets in that style below a 35, anything smaller than that will be an aftermarket sizing. A 30 is pretty dang small. If you think you have the skill you could solder and drill down with an 87 drill bit, which is .25mm - a "25" jet. It's definitely not easy to do when you get into bits that small though.

Have you checked the float height? For a PZ carb it should be set to 22mm (.866") and have 24mm of drop. Too high of a float can cause a small amount of extra fuel to be pulled under vacuum, which can make you chase your tail trying to get a tune figured out.
With a 30 pilot and the air screw pretty much all the way out and the idle speed all the way up it will maybe idle for a few seconds before dying. I tried jets in the 40's and the air screw in more but it got worse. I've never checked the float height, I'll do that.
 

noah9988

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20220610_123602.jpg
20220610_123656.jpg

12mm is from the bowl flange to the top of the float, which I'm not 100% sure is how you measure it. But 22mm doesn't sound right, at least not for this carb.

BTW, this is the one I bought: https://www.amazon.com/Carburetor-M...22&qid=1654879331&sprefix=pz22,aps,103&sr=8-2
 

DieselTech

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I know this is not the correct way to set float bowl height, but in a hurry I just make float parallel to float bowl flange. I think somewhere around 12mm is specs for that style carb.
 

Greg58

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This is the drill set I have, I use a torch to solder jets then use the hand drill. The smallest I've used is a #74 on nt jets.
 

ImpulseRocket89

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Not sure what clone that carb is, but a true PZ22 has a square flange with round floats. On the later, larger PZ carbs that came with rectangular floats the height was 14mm. You could give that a try, but being a clone, it's hard to say for sure what the proper setting is.
 

noah9988

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Not sure what clone that carb is, but a true PZ22 has a square flange with round floats. On the later, larger PZ carbs that came with rectangular floats the height was 14mm. You could give that a try, but being a clone, it's hard to say for sure what the proper setting is.
Yeah I realized that after I looked up a pz22 and it didn't look anything like what I have, lol.
 
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