When I 1st started working on it there was a lot of popping back in the carb and wouldn't run off choke,
I have cleaned the carb 3 times. Every passage is clear all just clean, new fuel cleaned tank and petcock. Timing is dead on. Adjusted the valves and sprayed everything with carb cleaner and wd 40 searching for air leaks. replaced all O rings also.
From cold starts on full choke, then go to half choke then when good and warm take it off. I drove it 10 miles and it ran perfect until the last 1/2 mile. The 1st 1/4 throttle felt like it was a huge flat spot but fine when I passed it. I pulled to park it and it died. Only way to restart was with 1/2 choke. It idles real high with the choke on.Starts off normal then revs up. when is cools off I can do it all over again. There is some signs of old grease buildup at the head gasket. I spray the area with carb or wd no change. I thought when the head expanded it sucked air. compression is great also.
Any ideas would be much appreciated.

 

crank seals leaking when they get heated up?

 

It sounds like a fuel starvation problem. Check fuel tank cap for proper venting. Ride it till it dies, open the fuel cap then close it and then try to restart it. Also, does it have an in-line fuel filter? Check it for clogs. Fuel line may be collapsing/kinked, too.

 

might try cleaning out the tank. might have crap in there sucking down to the carb. inline fuel filter will help to.

 

I thought it was a venting or dirty tank also. I cleaned the tank and petcock. New inline filter and fuel line. I had it where it would run thendie and could get it to start with choke and after playing back and fourth withchokethen none it would run again for a few minutes.thats when I pulled the tank and petcock. i had opened the cap thinking that was it.

Also when I started working on it the fuel adj screw The one in front of the bowl facing down was 3 1/2 turns out?

is the crankk seal on the right side, can I spray test itor is there 1 on both sides.

Thanks
EDIT: as far as the crank seals go. it a 4 stroke with no oil leaks.

 

Is the fuel filter housing only half full of fuel? Sometimes when I've put a new in-line filter on, I've had to prime the line before hooking it to the carb. Otherwise the fuel will not flow down into the carb. Take the fuel line loose at the carb and hold it down toward the ground and let a gush of fuel run out of the hose. Pinch it off and reconnect it to the the carb. Then try to start it again.