Setting my engine timing at 28 degrees at 3500 rpms I get backfiring/ popping

can this be caused by fuel starvation?

or is this because of another issue

i'm using the mark on the fly wheel to set timing

any tips on trouble shooting?

Well, I'm kinda going through the same thing right now. Yes, when it pops it is lean, as I understand it,. I really can't help you out much more as I am out of my league when it comes to carbs. I'm just learning.

not carbs

but i can increase fuel values

fuel injection? Hmmm... I don't really know why that would be happening with fuel injection unless there was an exhaust leak.

Is it popping out of the intake or exhaust? Lean pops are out of the intake.

is your ignition system healthy?

custom setup?

Always verify mechanical integrity first.. This means a leak down and compression test are done first.

If the engine checks out with no mechanical issues then I'd say you more than likely have a funky injector and that causing a single cylinder to lean out. if it does this on acceleration, try both low and high speed ACCEL enrichment and see if it gets better.