I have fitted a 256mm PHBH 4 stroke carb which has been converted to 2 stroke to a 200 stage 4 engine.
The jetting is currently 128 main jet, AV266 atomiser, needle X2 and sterter jet 55
The engine will only start if i cover the carb mouth with my hand and with the choke out and it will only keep running with the choke out it revs cleanly with the choke out, put the choke in and it dies.
Any advice on jetting a 26mm to suit a 200cc stage 4.
Jetting Advice
Anybody any ideas, why does it tick over smoothly with the choke out and die with it in, whatr do i need to change, up my main jet, atomiser ?
ya must have big hands. 
The only jet size you haven't mentioned is the Pilot, and that i suspect is where your problem lies.
Pilot jet is 55 or as i called it a starter jet in my first post
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col68
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Have you tryed a x7 needle ? I have a 30mm phbh on my stage 4 200cc 53 idle, av 266, x7 clip on second clip down from top, 128 main with a ramair filter. A little rich at that but running in still. hope this helps . col
In that case, what size Choke jet are you using? I would expect a 70.des wrote:Pilot jet is 55 or as i called it a starter jet in my first post
What your describing sounds like it's running very weak and with your settings it shouldn't be so i would first check that your mixture screw isn't wound right in and then clean out the pilot circuit with compressed air.
If that doesn't work i would say you may have a nasty air leak.
If that doesn't work i would say you may have a nasty air leak.