Motorcycle Repair: Yamaha 85 XT200 timing, air gap, cylinder compression

Question
I have rebuilt top end and am getting kick back
when I try to start bike. I have around 100 psi, expect it will increase when I get it started and rings seat better. I have Yamaha manual and timing
light.
I have checked timing marks for valves couple times. I get spark with and without 6V battery but don't know how to check timing.

Pick up coil doesn't seem to be adjustable. Could faulty CDI unit make timing off when tryng to start?

The kick start kicks back quite strongly every couple of kicks, there is no smoke or noise and
it won't start. After while it will stop kicking
back expect it is flooded.

Thanks Garry

Answer
Hi Garry,

Compression kick-back may be attributed to incorrect valve timing, however, kick-back is normal.

Pick-up coil is non-adjustable. Measure the air gap between the pick-up coil and it's trigger. Keep these parts as a matched set.

The CDI is likely working properly. When bad they usually produce a faint arc, or no arc at all. A defective spark plug or ignition coil may arc a plug's gap when grounded to the engine, but not arc under the load of cylinder compression.  

I would need to work with the XT to diagnose the problems.

Respectfully,
Mark Shively