My '73 does the same thing so I put it on a dyno for a better tune. The trick is to tune the idle hot, this will require you to warm it up before riding it, mine takes about 5 minutes. Mine will barely idle cold so I use the choke for a minute or so, just about half choke does it for mine. It idles at 14.5 to one on the O2 sniffer which is really close. Checking for leaks is a great idea but if you do not find any, adjust the idle down while it's hot

 

Thanks good to know I am going to try this As we speak the weather has been to cold to try this Thanks

 

Hey Race you finally got your bike running good I remember you had a carb problem

 

It is important to first adjust the idle mixture [pilot screw] when the engine is fully warmed up, then adjust the idle speed; then repeat to really fine tune it.

Adjusting the pilot screw is a little tricky, especially if you are not experienced. You have to be careful to not burn your fingers. You may have to raise the back end of the fuel tank, depending on the space between the tank and the carb. And have a very short screwdriver. You have to blip the throttle occasionally during the process. And be listening carefully to changes in RPM as you adjust the pilot screw. Then leave it set about half way between the upper and lower stall RPMs.

 

Mine ended up a valve guide problem, both exhaust valve guides didn't have the proper clearance but the carb was off too. Runs like a champ now

 

Did you do the work on it yourself? I do remember you were getting fustrated with it