anyone adjust their valves on the ltz250 ?

I got the plastics and the gas tank off, got it to top dead center
removed the intake/exhaust cover nuts to access the adjustment
screws but .........................

I cant even get the angled feeler guage in there

I have searched the net for a service manual, either online or to purchase but no luck (surely they make one ?)

it dont look too hard to understand, just a screw with a jam-nut
open it to spec and tighten back down but I cant get a guage in there...............................

what am I doing wrong ?

I dont want to drag it 45min to the suzuki dealer
thanks
Jimmy