Stall when hot.

[Goggles Pizano]

I know I've seen a post or two (probably one of my own) but search is beating me up right now.

As soon as I hit 220* the bike will not run right.  Too much gas or lack of spark/timing is my guess.  Seems to be the magic number, not sure why.  Cooling down will only help a little after reaching that temp.  Can tell problem is coming when I get above 200*.  Hesitation, backfiring, no power in upper rpms, etc...

Background:
900 swap into 620 bike.
Using 620 electronics
Custom map using PCIII from local non duc shop, but qualified PCIII dealer/tuner with dyno. (Ran GREAT for a few months)
New battery. (New for season, problem showed up this season as well. does PCIII lose program with battery disconnect?)
Since problem:
Replaced plugs, wires, and tested coils (same readings on coils with problem present and not)
Both cylinders are a similar temp based on touch only. (they are both firing as far as I can tell)

I smell a lot of gas coming from exhaust when prob is present and bike will stall at idle.

Does something change on the 620 program once it warms up that might be causing this prob? If so why did it take so long to surface?

Thank you for any advice on this.

[Howie]

Temperature sensor?

Tight valves?