[Mr. Lew]

SO I took it out for a quick spin to break in the new cam and about 20 mins into the ride it began to backfire and pop. I shut it down and towed it back. When I got home I pull her apart and discovered that the locking nut on the decompression stud had COME OFF! The stud had backed itself out so that it was only hanging on by one thread. Luckily the the nut was lodged up against the wall of the head and the nut on the stud. Nothing fell into the Bottom part of the engine. I double checked that nut was tight so I am unsure what caused it to do it.
I put back it together, I adjusted the decompressor, and ran a compression test. It cycled and passed with 56 psi.
My questions
1. Is there anything I should check before I try starting it? Should I be looking any damage
2. Can I use lock tight on that nut, to hold into place?
Thank you

 

[hoser]

Wow, you did get fortunate. The torque on that nut is very low, and I’m quite surprised to hear it loosened, I’ve never seen that myself. It wouldn’t cause any other damage. You could use Loctite on there, it will just be harder to break loose when doing maintenance.

What I wonder is why it would be backfiring if the stud backed itself out, when running that arm has no affect on anything, and if the arm backed out it wouldn’t be hitting anything anyway. Kinda weird.

 

[Mr. Lew]

T

Wow, you did get fortunate. The torque on that nut is very low, and I’m quite surprised to hear it loosened, I’ve never seen that myself. It wouldn’t cause any other damage. You could use Loctite on there, it will just be harder to break loose when doing maintenance.

What I wonder is why it would be backfiring if the stud backed itself out, when running that arm has no affect on anything, and if the arm backed out it wouldn’t be hitting anything anyway. Kinda weird.

The rectifer had a short in it. When i got home i did a voltage leakage test it was .02 mV and the battery voltage was at 11.7 volts. I replaced it and now there is 0 voltage leaking. I believe the backfire was the result of stator not charging the battery.

 

[Mr. Lew]

Wow, you did get fortunate. The torque on that nut is very low, and I’m quite surprised to hear it loosened, I’ve never seen that myself. It wouldn’t cause any other damage. You could use Loctite on there, it will just be harder to break loose when doing maintenance.

What I wonder is why it would be backfiring if the stud backed itself out, when running that arm has no affect on anything, and if the arm backed out it wouldn’t be hitting anything anyway. Kinda weird.

The popping was because the air fuel mixture screw vibrated out. I put it back together. It still will not start. Sometimes it will start up only to die. Braaap then nothing. I am lost and need help.
I have
1. Set the timing see pics
2. I have spark see vid.
3. I have set the valves to spec
4. Battery @14.1 volts
5. No shorts in the harness
6. Carb is cleaned all jets and passages blown out with compressed air. Air fuel mix screw is at 2 turns. However a change of 1 revolution +/- makes very little difference.
7. Spark plug is wet when i pull it.
8. Decompressor is set at 56 psi.
9. Conducted a leak down test @100psi it was 94psi so a loss of 6%, which is pretty good.

 

[Mr. Lew]

Here is a link to spark vid

Your help is greatly appreciated as i am lost on what to even look at to try and fix this.