What I suspect is that the intake valves are open on the compression/exhaust stroke when the piston is going up.

If it's one cylinder, then it's a valve adjustment, seat problem, burned valve, or flat exhaust lobe issue. They didn't leak when you had it apart, so the valve and seat are most likely alright.
If it's all 4, then it's a cam/crank timing issue.

Have you looked at the cam lobes to see if they are going flat?

 

https://cbrforum.com/forum/f4i-main-...02-f4i-121020/

im reading this thread.. and the guy recommends that you rotate the engine 4 rotations and recheck if the markings a still lined up. ill open it up again..and see.. ugh

 

readjusted everything. still does not start. no more hot air thru the throttle...only cool air coming out. i will do compression test tomorrow.

is the cam setup for all f4i engines the same?

what do the dots on the cam rods for?

 

it fired up! finally! i just need to put the exhaust together and add some coolant.

long story short...so the cam rods have these markings... curves ..slots.. that are supposed to be lined up with the markings/curves of the valve cover thingy. once i figured that out, I was able to readjust all the valves properly. Tomorrow, I will put everything together and hopefully...get to ride it. RoaR!!!

 

Finally.....I was running out of ideas. It seemed that it was going in circles. Good deal, glad it works!

 

yeah. thanks for the help demon and everyone else. hey, do you live near riverside?