Finally got her all together!!!

Feb 8, 2021
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I'm so excited and stoked for tomorrow everyone, I just finished my first motorized bicycle. I've got to get gas tomorrow and then I'll mix the two and fill my 4L tank up and ride, then I'll officially been apart of the motorized bicycle club right??? I ended up purchasing a 38T sprocket and adapter and she worked beautifully. Now I do have a little problem I haven't started this engine yet and I've fucked with the fuel and air screws on the carburetor cause I want thinking when they said make sure everything was tight and I didn't remember how far they was screwed in our out, it should still start right I'll just have to **** with it heavy now to find the perfect idle and what not. All in all I'm excited about this and can not wait to ride her. I need to make her!!!
 

wrench

Active Member
Aug 20, 2019
150
46
28
So Cal
The air fuel screw can be only 1/4 or up to 1 1/2 turns out
To get a ball park idea

Turn the air fuel mix screw out 1 turn 360* When it starts adjust it to where ya get fastest idle then back off screw 1/16 of a turn if that

Now set the idle, You'll hear what sounds good.

When starting the bike again if it don't start ya probably backed off the idle too far.
 

wrench

Active Member
Aug 20, 2019
150
46
28
So Cal
China PZ-20 Kei Hin knock off carb

The top screw is forward on the right side of the carb - Idle screw
The Idle screw adjusts the carb slide up or down, that's the part the throttle cable is hooked to

Air fuel mix screw is lower to the rear of the carb above the float bowl and by where the air filter mounts

On the right side of the float bowl there is also a drain screw
The drain screw is the lowest screw on the carb and there is a nipple to attach a hose
 
Feb 8, 2021
30
12
8
28
China PZ-20 Kei Hin knock off carb

The top screw is forward on the right side of the carb - Idle screw
The Idle screw adjusts the carb slide up or down, that's the part the throttle cable is hooked to

Air fuel mix screw is lower to the rear of the carb above the float bowl and by where the air filter mounts

On the right side of the float bowl there is also a drain screw
Thank you for your help. So what I'm going to do is screw the A/F screw in all the way then bring it back out 2 full turns out. Then I start the bike and I adjust the idle screw accordingly until she sounds about right! Am I correct with this?
 

wrench

Active Member
Aug 20, 2019
150
46
28
So Cal
To get a ball park idea

Turn the air fuel mix screw out 1 turn 360* When it starts adjust it to where ya get fastest idle then back off screw 1/16 of a turn if that

Now set the idle, You'll hear what sounds good.

When starting the bike again if it don't start ya probably backed off the idle too far.
 
Feb 8, 2021
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Hey also I've noticed from alot of videos I have the cap where the spark plug goes in backwards is that okay will it affect it any or should I turn it to where the spark plug is facing the front tire like I see in other people's videos??
 

Sidewinder Jerry

Well-Known Member
Dec 19, 2011
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Rockwood, TN
The best fine tuning device you can use is a tachometer. You can buy a tachometer/hour counter fairly cheap off eBay and Amazon. Then when you're doing your tinkering adjustments you'll know precisely what your engine is doing.
 
Feb 8, 2021
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The best fine tuning device you can use is a tachometer. You can buy a tachometer/hour counter fairly cheap off eBay and Amazon. Then when you're doing your tinkering adjustments you'll know precisely what your engine is doing.
Okay thank you very much sidewinder jerry I appreciate all your help. I'm making a list for my next build lol. I want to make a chopper or one of those gangster bicycles lol
 
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wrench

Active Member
Aug 20, 2019
150
46
28
So Cal
Hey also I've noticed from alot of videos I have the cap where the spark plug goes in backwards is that okay will it affect it any or should I turn it to where the spark plug is facing the front tire like I see in other people's videos??
The head (cap) can be turned so the S/P is facing the front or rear.
You also can face the S/P to either side, but in order for air to flow across the cooling fins properly ya should face the S/P to the front or rear.
The reason people face the S/P to the front or rear is decided on where they mount their electrical so their S/P wire can reach the S/P
 
Feb 8, 2021
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The head (cap) can be turned so the S/P is facing the front or rear.
You also can face the S/P to either side, but in order for air to flow across the cooling fins properly ya should face the S/P to the front or rear.
The reason people face the S/P to the front or rear is decided on where they mount their electrical so their S/P wire can reach the S/P
Okay cool thanks so here is my new problem. So while riding when I go to come to a dead stop my bike will cut off instead of idling why is this?
 
Feb 8, 2021
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Idle screw adjustment is my first guess

Clutch adjustment is my second guess
Well I got an even bigger problem lol. She is not rideable right now. My damn chain tensioner from all the vibration turned inwards to the spokes and got jammed in there and busted and popped out like 6 spokes, so that rim is trash now LMAO. I already ordered another one, now I got to get a new and different tensioner.. smfh!!!
 
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Feb 8, 2021
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Well I got an even bigger problem lol. She is not rideable right now. My damn chain tensioner from all the vibration turned inwards to the spokes and got jammed in there and busted and popped out like 6 spokes, so that rim is trash now LMAO. I already ordered another one, now I got to get a new and different tensioner.. smfh!!!
Idle screw adjustment is my first guess

Clutch adjustment is my second guess
Yeah I want ahead and bought one of those chain tensioners that bolts to the engine, I'm even going to loctite the damn thing this time lol
 
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