Stall out dead

[Oldmanmoto]

So, forgive me if topic approached before, also I am not too familiar with these moto,s.
question please, after driving for about 1/2 hour bike dies, cool or let sit for ten minutes will run again for about 5 minutes, repeat same result.
Recently changed to 72 cc upgrade and all seems better except new problem.
Found one wire loose that goes to auto choke which possibly may have allowed choke to close on me, was kind of surprised as all lights went out and she just died.
Few minutes later off we go, had a weird noise before dying, thought of clutch and variator but they look ok. Cannot describe noise exactly as I cannot hear well but could be choke closing and engine leaning out.
Will try to find new plug later as we are camping out, no plug even close by. Will check for vented gas cap, not sure what else to look for.

[chaz35]

do you have air cooled or liquid cooled engine?

[Oldmanmoto]

Two stroke air cooled 49 cc

[Oldmanmoto]

Shoot forgot to say it is a kymco, 2007 model super 9 with about 2k miles only

[Dabby-D]

What carburetor size and main jet are you using? The manual chokes are much more reliable, the ones ON the carb vs with the cable leading off the carburetor are better. The Auto-choke will usually only make the starting difficult but you should be able to start it with the throttle open a bit. It will soot out your engine a bit too. The sounds of your problem sound like a carburetor issue, throttle control screw out of wack or the jetting.

[CROSSBOLT]

Did you check/set the piston ring end gap on the 72 cc kit?

Karl

[Dabby-D]

I learned the hard way that the oil pumps can't keep up with big bore kits. What ended up happening is that the lean condition made the idle go HAM as the piston ring and piston were getting scrapped on the top and bottom, the spark plug ate sh** and the platinum pin on the plug flew out with the loss of compression that turned vacuum. it bounced to the top and grinded the piston, then went to the bottom, scraped again before getting exhausted out. It chipped the Nikel plating slightly between the exhaust port, but that seems an acceptable spot. The ring got melted onto the piston and i had to remove it with a metal wire around the circumference. the compression went to nothing and resetting the piston ring created 30psi, I'm re-sanding the piston channels to try again for more compression, adding a teaspoon of oil in the cylinder before retesting gave me 100psi. I may have to break down and order a new piston ring, but the learning process is priceless. I like to work on things, so i don't mind, besides the speed improvements are so worth it. I removed the oil pump and blocked it off, I finally graduated to premixing at the pump so i can blap to people about how cool my ride is now and shock all the street bikes that think I'll be slow. Sounding like a leaf blower finally gets car tards off their damn phones to see me. LOVE IT, even went to the beach to find someone else's GF getting real comfy on my bike    If your stalling, make sure, its not a lean condition like mine, or your going to have internal damage and be pissed. Oil pumps suck, I think it would take an exhaust testing module to even make sure your at the right mix.