Tech help

[Dave Withrow]

I have a problem with a 1981 KTM 250.  It wants to run lean.  The carb is a Bing 54/38/107.  I've raised the needle and completely closed the mix adjust but it simply makes no difference.  It idles high no matter where I set the idle screw.  To me it acts like too much air.  Should I go larger on the main?  I've run 1 Hare Scramble with it and I noticed pinging about 3/4 of the way through the run.  Thanks for any help.  GO PENTON!

 

[Rocket]

Sounds like you have an air leak somewhere, mag side crank seal, base gasket, or intake gasket or mounting flange of carb.  With it running, spray carb cleaner around the different areas and see if the RPM changes, that will indicate where the problem area is.
Rod