[NMKawierider]

I believe that's just a bolt going into a threaded hole in the casting. Do double check if there's a nut on the back side though. If it just spins, then it was installed cross threaded and its stripped. You will need to apply outward force on the bolt while rotating it counter clockwise and hope an old thread will catch enough to bring it out. While using something to pry-up on the cover against the bolt, with an end wrench, work it back and forth. One step to the right and two to the left. Spray some PB or WD on it too..try to get it down into the threads. Might just get lucky. Otherwise you may need to cut the head off then deal with the shaft afterwards.

[Davydo]

Is there a guided in the forums in how I'm supposed to make that adjustment?
Or is this something I should have the service manual for?

500 miles, you definitely need to check valve clearance, mine were tight when I checked at 500 miles and I had been running the unifilter since 120 miles. I never had any starting problems though. If I remember the valve clearance specs are .08 - .12 mm intake and .12 - .18 mm exhaust.

[castortroy]

Thank you everyone for the information.
It turned out to be the valves, just like it was said in this post.
After adjusting to the proper specs, it fired right up and ran great.

Thank you!

[CFM500Trail]

I am having the same issue of not starting.  However, I had some backfiring and oil smoke, was running fine and the next day would not start.  Would all of these symptoms point you to this same issue potentially?

[NMKawierider]

I am having the same issue of not starting.  However, I had some backfiring and oil smoke, was running fine and the next day would not start.  Would all of these symptoms point you to this same issue potentially?

All except the oil smoke so check the valves anyway. Part of the due-process.