Riding my sym then the engine cut out now wont start did this two days first day started again not today

SOURCE: engine misfire and cutting out when running at normal engine temp

Make sure your fuel tank vent is not plugged. To see if this is the problem, the next time the bike starts acting up, stop and open the fuel tank. If you hear a whoosh of air being sucked in you know your vent is plugged.

The C8HA is still available, it is NGK stock number 2168.
Good luck.

SOURCE: cbr 125 choke problem

It sounds like the choke line may not have been routed correctly when the new one was installed. Remove the gas tank and check to see that the line is not being stretched anywhere along the way AND that the gas tank when re-installed is not stretching the line. The line may have been kinked when installed. Look at the mechanical movement of the choke at the carb. Does it operate freely? Remove the air filter and look inside the center of the carb, (you may need to use a small mirror for this), does it look like the choke is opening and closing properly when the choke is moved on and off?

SOURCE: timeing a yamaha 175 enduro

Without the year of the bike I am hampered. Lets assume it is an older bike and has a set of ignition points and not a CDI model.
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Pull the cover off the shifter side of the engine. Remove the spark plug then turn the flywheel so you can see the points. Oil on them? Dirt, or rust? Next check the main bearing. Do not rotate the flywheel but instead hold the flywheel firmly and lift it up and down, left and right. Was there any movement or was the flywheel rock solid?
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I am willing to bet that the points were dirty and there was a lot of play in the crank bearings. If so, you will need new crank bearings and seals plus new points and condenser. The engine needs to tear down into about 75 parts in order to replace the bearings. The job requires some special tools to remove the flywheel and clutch, plus a crankcase separator the split the gearbox.
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This is not a job for the beginner. I suggest you have the shop do the work and also that you spring for 3 more bearings and seals plus a fresh cylinder bore, new piston and rings and a new spark plug. You now have a brand new engine that should run well and last for many years. Please rate this solution. Thanks

SOURCE: i have a cpi sx 50 cc with a big bore kit 80cc i

sounds like an ignition problem namely the coil or module. you might check to see if these are warm to the touch or hot after riding your 5 min. if so a meter check will determine if replacement is necessary. also check for loose leads anywhere. also make sure your plug is good and the right heat range for the bike. i assume you are saying it quits running but doesnt lock up. if its seizing up then your rebuild kit is likely the culprit and will have to tear it down and check clearances with the rings and cylinders and piston etc. good luck.