Ive got one. I know what you mean, you get half worn out starting the damn thing!!!!
Play with the jetting all you want. The root cause is this.
It has so much compression that it is hard to kick it over with enough revolutions to draw fuel into the cylinder.
Pull it out after sitting a week, and there is of course, NO fuel left in the jug at all. Sucking a fresh charge from the carb takes more revolutions than an average kick will get you.
Ive done many things. Bump the kicker little by little til it gets tight, then just a HAIR more. Then jump up and kick it HARD.
Spray some carb cleaner into one of the T vent hoses...that works well also.
Ive gone so far as to place a small petock inline with my boost bottle hose, and I have a lab style squirt bottle with some premix in it, so first start of race day, I twirl the petcock open, give it a squirt, twirl it shut and two kicks tops.
Mine still knocks a bit when hot...gonna try some 110 octane next time out.