My new to me beta 125 boggs like crazy on start up. It acts like the engine is not warmed up despite it running / idling for 5 mins. It revs fine stationary then when you try and ride off it boggs. It nearly dies it boggs so much. This goes on for another 5 minutes then it just clears and runs perfectly for the rest of the session. This happens every time I have ridden it. Air screw is 2.5 turns out. I notice on a cold start up, having the choke clicked on makes it rev far too high for a cold engine and I have to feather the choke without clicking it fully on to get it to run for the first minute. Then it idles ok. I have cleaned out the bowl and lower section of the carb with compressed air a few weeks ago. Any ideas ? Is the choke adjustable or should I adjust the air screw ? Fuel cap pipe is not blocked.

 

Edited March 30, 20215 yr by gazzaecowarrior

The idle circuit sounds like it is right on the edge of lean.  I suggest:

•  clean the idle circuit with a carb cleaner, be sure to remove the idle mixture screw and pilot jet to spray through all passages, then follow up with compressed air.  Look though the pilot jet to make sure it is not plugged.  While it is apart you might as well clean everything.
• the mixture screw is an air screw. try adjusting it in progressively.  Don't go below one turn out.
• Go up one size on the pilot jet. (you could check first to see if you have the factory recommended pilot jet size)   

51 minutes ago, mcman56 said:

The idle circuit sounds like it is right on the edge of lean.  I suggest:

•  clean the idle circuit with a carb cleaner, be sure to remove the idle mixture screw and pilot jet to spray through all passages, then follow up with compressed air.  Look though the pilot jet to make sure it is not plugged.  While it is apart you might as well clean everything.
• the mixture screw is an air screw. try adjusting it in progressively.  Don't go below one turn out.
• Go up one size on the pilot jet. (you could check first to see if you have the factory recommended pilot jet size)   

Thanks for the info. Will try that