Pwk jetting question

If it runs fine cold then starts acting up as it heats up.. it’s a good chance there’s an air leak.

I had a case leak do me the same thing. Run fine cold and bad hot. It drove me batty trying to run it down.

It is common for an engine to change the way it runs as it warms up but not so drastic as to indicate bad tune. My engines tend to idle a little higher and not be as spunky cold as running temp but it settles down within a couple minutes of run time.

A small piece of my case center gasket broke and pushed out in the area of the clutch shaft and I didn’t find it until I tore my my engine down and saw where oil was tracking into that area. Spray testing didn’t find it.
I went in circles with jets and needles trying to fix it.

Not saying this is your issue. Point is.. sometimes air leaks are difficult to run down.

If the tune changes drastically after the engine heats up there’s a strong possibility an air leak somewhere that is responsible for this. When the leak shows up the tune goes leaner.

A thing you could try to prove whether it’s an air leak or the carb/reed is put the stock intake and carb back on and see if it responds the same way.
The stock. Carb and intake. Won't. Work with the windowed piston tho, will it? Believe me I had thought about that before but I made up my mind if it ever came down to where I did have to put my original piston and intake back on then it was going to stay that way. But if I can run that HT card and intake or the window pissed and I'm definitely going to try it out.
 
I do not think the window piston will run correctly in your application.

A leak down test is the correct way to find an air leak but it’s a bit involved.

 
I do not think the window piston will run correctly in your application.

A leak down test is the correct way to find an air leak but it’s a bit involved.

Yeah that was definitely in the back of my mind. I had read something similar to that a few days ago and thought about checking it out. I got a compression tester at home I haven't even busted the package open yet, I know I can find my answer by looking but I was just curious if anyone here would know how many psi am I supposed to have in my cylinder since it's a hundred cc motor.? Another thing I need to mention that I really just realized this morning how big of a deal it was, I'm running through gas like a fish runs through water. Usually on one tank of gas I can go back and forth to work for 3 days and that's even making side trips going here and there. But I've had to add gas to that tank twice in 2 days. And it just dawned on me this morning on how much I was really running through, so that kind of reinforces my leaning towards too rich. But at the same time that was before all the joints and seals got sealed up on the Reed valve, and it was leaking gas.
 
Leak down psi…according to the link... 5 psi for 5 minutes..
1 psi bleed down in the 5 minute test is still acceptable.
Anything more>>>look for a leak by spray bottle
 
Dropping the main needle (clip towards flat end) will lean out your mixture.

If you have no air leaks (tested by spraying with water or carb cleaner and checking for rpm drop/rise) you need to tune based on sound/feel and your spark plug deposits, not on how the carb looks.

It's worth mentioning that some of these carbs need an air filter restriction to run properly.

Run it normally, but not too hard, shut it off without idling and pull the spark plug, post a picture here.
Ok the first pic is the plug after I cleaned it up a bit, I made sure to really clean the bottom off so we could get a good deposit if there was one. The second and third pics are after, with oily ring around the bottom and more black than when it went in. I fired it with choke for a few seconds and then regular, and just cruised around the parking lot for a while. And today there's not much wind as there has been so i noticed quite a bit of blue smoke coming from the exhaust. Had a little at idle after it was warm, so I adjusted the air mix and got the idle leaned out to a fair point but it's backed prettyuch all the way out, and once the needle hits main it's smokey again and moooooing.
My jets are supposed to be here today, I'm at 105 main, I think all I need is the 100 and it'll work out.
 

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Looks good just a little rich
Yeah I'm sitting here stressing the Amazon order now, keep checking the damn thing every 30 minutes see where my jets are at. I get off work in an hour and I was kind of hoping they would be there when I got there. But my pops always used to tell me "wish in one hand, and s*** in the other, see which one fills first"
 
Yeah I'm sitting here stressing the Amazon order now, keep checking the damn thing every 30 minutes see where my jets are at. I get off work in an hour and I was kind of hoping they would be there when I got there. But my pops always used to tell me "wish in one hand, and s*** in the other, see which one fills first"
I do the same thing when I order stuff lol
 
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