Simple fuel screw question

Patton wrote:

Davestradamus wrote:

...cold starts just fine. 1/4 turn? ... Screws are set at 1 1/2 from lightly seated....

Would go in 1/8 turn steps counter-clockwise to lean the pilot circuit. Usually, the optimal setting is where best low idle performance is determined.

Leaning the pilot circuit should not degrade cold starting ability, because cold starting mostly depends on the separate enrichener (choke) circuit.

Good Luck!

Patton, sorry but I must disagree. The idle mixture must be close to right for the enrichening/choke to give the correct cold start mix. As well as well synced carbs.
If you are not leaving enough time for the motor to warm up you will get a hesitation. Your carbs should have accelerator pumps. They could be the problem. This mostly sounds like a fuel problem. Also, check your battery. Weak batteries, poor spark or dirty plugs can give the same symptoms.
As to your carbs being correct, it's possible after 30 years the carbs are from another 650. Just a thought.

The correct size carbs for your 650 is 24mm throats. Check to see if someone put 26's on the bike.

EDIT!! i looked again at your carb pic. those are 26's from a later 900 or a 1000.