Modern Vespa

My Piaggio is having a hard time starting when the engine is hot, starts first time perfectly every day, if engine is hot and running and I stop and then immediately re-start it will fire up, but not after it's been sitting awhile, like while eating lunch or shopping in a store or even sitting in front of my house for an hour or two will be it be hard to start. Giving it a lot of gas in this situation is the only way can get it to fire and sometimes I have to crank it quite a bit and give it a lot of gas before I am able to do so, several cranks for several seconds while opening throttle a good ways. I'm worried I will wear out the battery/starter or it will eventually fail to start completely and I will end up getting stuck somewhere.

Some videos I watched got me thinking it might be the evap collection system, maybe it needs to be removed? Or possible vapor lock? Fuel delivery system issue? seems to have started doing this when Summer kicked in, daytime highs here average low to mid 90s all summer long and routinely get up to 100+. I also did have the muffler removed when I got the back tire changed right before it started doing this, and it does seem to be making a slight 'backfire sound' after a hot start, I'm not sure if this was there before or not.

Any ideas? Thanks

Pull the evap line from the carb. You don’t need to eliminate the whole system.

Check and adjust your valves.

Will do. How hard is that? never done it before.

is it ok to leave evap line disconnected or do I need to plug or remove it?

You can leave it dangling and the carb inlet open.

If it's idling off the throttle screw, and not the idle circuit, it will be very hard to start when things warm up.

I believe i had a carb issue, ever since I did a hot soak with high concentration of chemtool this hot start issue has been greatly improved, it also improved my idle, less revving and more stable.

Did you check the valve clearances?

No, but its at the top of my list.