[bigste_kx125]

my kx 80 wont start i was riding it and it was fine until i let my cousin have a go and it was running fine until he was turning around and it just died on him, now we thought it was fuel, so we put some more fuel in still not starting, so i changed the piston and rings, then there was a change it was trying to start the bike then started to back fire and it tried to start ya could here it running but then when he put throttle on its died and backfired...we need help and fast please !!!​

 

[bbap]

When you changed out the rings and piston, did you notice if the lower end was full of fuel? First guess is that it is flooded. I'm making an assumption that you have decent compression (100lbs or greater), if yes:

1. Pull off the exhaust and see if you have fuel in there. If yes, drain and, then
2. Pull the spark plug, push the plug wire out of the way, put the kill switch on OFF (no spark to plug). Kick it over about 50 times until you see no fuel spraying out of the plug hole.

3. Put plug back in, switch ON, check for spark. If yes (continuous each time you kick):
4a. Put fresh plug back in and give it a try. If it works, great, if not: you likely have carburetion problems and there are numerous threads here on how to clean, starting at the air filter and ending at the carb.
4b. If No or intimitent, check wiring from kill switch on down for any shorts

 

[bigste_kx125]

yes when i did the piston and rings there was fuel in the bottom end, i dont understand cos the bike use to kick up 1st time every time.. i will try the things you have said thanx for ya help ​

 

[bigste_kx125]

also if this is any help my cousin was riding the bike with the choke on full, and thats when i just cut out and wont start again now

 

[bbap]

I've had to remove the jug and drain the fuel out with a small hose before. You may need to do this if you can get enough of it out to start. Once it starts, let it run at .25 throttle for about 10 minutes to clear it completely. Then, only use the enrigher/choke to start a cold engine.

 

[kx80 Cam]

could be your carbi mines playing up too but im fixing it or it could be a spark problem check the spark plug lead too