Here is the problem. Son stopped his 125 03 at start of a section whilst waiting in turn. This was towards end of trial with no suggestions of problem with bike up to that point. No missing, no fluffing, was starting first kick. Kicked it to get going again and nothing.

Got back to workshop. We have spark (not the brightest but consistent). Kill button works OK. No loose wires anywhere. Stripped carb and rebuilt. Still no response from engine. Tried the Gas Gas jerk (put in gear and rock). No go.

Anybody any ideas

Found a possible from Totalshell in answer to another question. I will try the lie on side / fill carb chamber trick.

check the length of your fuel pipe and make sure your fuel flow into the carb is consistant. i had this problem on recieving my sherco a year ago and the fuel pipe length was to long and starving the bike of petrol.

What got said from total shell ont the topic i started for a mate of mines brothers bike , i did that to it and then it went on 1st kick hope thats all it is for you as well.

This may sound daft but spark plugs can break down under load, when they are laid on the barrel or head (to earth them) you will still get a spark try changing the plug could be a simple fix, no guarantees tho. :snowman: