98 FC501 jetting and carb adjustment

Hi, husyrdaddy.....
I still have oem Dellorto PHM40 on my '98 fc. This is my carb set-up, sea level, coast of Maine:
Needle - K51, 3rd position up.
needlejet - 270DR
main jet - 172
pilot jet - 35, can go to 32 , more effect on idle.
start jet - 45
float needle & jet - 300
Mixture screw @ 1 7/8 - 2 1/8 turns out
Idle screw @ 5 +/- turns, idles at 1525 to 1575 using my Sendec hourmeter/tach as reference.
Cold start, all the way down to 0 deg, 2 kicks, hot start 1-3 kicks.
There shouldn't be much, IF ANY, slack in your throttle cable, should start to open slide at first motion of right grip. Lube and adjust cable for no-slack, or replace it- it may be holding the slide partly open.
When I need parts for the Dellorto, I get them from http://www.herdan.com. There is a gal there that really knows the business, super helpful. Much less expensive than other sites.

Sounds like you have the slide open a bunch to get an idle and are past the angled nose of the screw thus little effect. Hard starting also points to excessively open slide. Make sure the air jets in the carb bell are open and not plugged with filter grease. Check needle and needle jet for wear and float level. Adjustment screw meters idle fuel.
dan