1980 650 ldt carb issues

Howdy all, I have a 1980 650 LDT I got a from a guy who "lost" the factory air box and replaced it with air pods. The bike has factory exhaust and he was told to change the pilot jets to two sizes bigger and he would be fine. I knew that was wrong, but am not sure where to go to tune it right.

It also has 110 main jets(also way off for factory, 97.5 is about factory correct?!?!?) and I have replaced the original pilot jets. Bike hits and starts for 2-3 seconds then dies. This is with the choke fully on. I have air screws at 2 1/4 out and adjusted a full turn either direction 1/4 turn at a time and no help. I also have the needles at the 4th postition as per factory specs.

I am almost positive the 100 main jets are too big. I even doubled checked compression we are even across the board on that also.

So, with a factory exhaust and air box, any ideas of where to start the jetting at? I am thinking in the 100-105 range, if I even get that big.

Thanks for the help.