Motorcycle Repair: 250cc 75 bultaco wont start, valve work, blue spark

Question
hi i have recently rebuilt a 75 250 sherpa from the ground up. last
night i had it running but it would cut out after a few seconds.
today when i have tried , i cannot get the bike to fire at all. i
have checked the plug, i get a nice clean blue spark. i also am
getting fuel to the plug as it is getting wet after a few kicks. the
points have been set back to their original place pre rebuild. i have
also changed the condensor and tried a differant carb still with no
joy. i even tried heating a plug up and pouring fuel straight into
the cylinder ... still wont fire . any ideas?

Answer
Mark,
Try adjusting the float level in your carburator.  If the floats are set to high you won't have enough fuel in the bowl to maintain idle.  Also be sure you needle valve is not sticking, this will restrict your fuel flow.  The floats and the needle valve work together to maintain proper fuel level.

Mike