Engine Trouble Really strange problem with 80cc engine

[Wrench]

Thanks dude it seems the only way for me is to use helicoil.

If that bolt is a 6mm thread you can use a long shank tap and tap it to 1/4" x 20 thread
You won't have to split the case using long shank tap - blind tap

1/4" is the next bolt size up from 6mm, It's so close ya don't have to drill before tapping, just tap the stripped hole
20 tpi is more course than 1.0mm and will have less chance of stripping the the future

 

[Bikemovile]

Did you figure out the original problem?

I only have been using the bike some weekends.
No more than 40 kilometers in total.
I'll change the nuts on the head to normal ones and adjust the magneto gap and keep testing.

 

[Bikemovile]

Today it was really difficult to make the engine run, but it turn off at idle.
Then I tried to start it again but after 100 metres running bad and "popping" I listened like a explosion and stoped trying.
Dont know what to check at this point
The head nuts are new and tight.
May be air leak due to the casing bolt?

 

[Whitewill1412]

Have you made any carburetor adjustments?

 

[Bikemovile]

Have you made any carburetor adjustments?

Set the needle on the 2 leanest position.
Ajusted the float to 21 mm.
Made a couple of drills on the filter case for improving air flow.
A couple of drills on the exhaust also.

 

[Bikemovile]

Just tryied to start it with the gas switch on the line in the off position(no gas to the carb).
It STARTED FINE and then opened the gas and runing good but after 30 seconds on idle it dies.

 

[Gordy]

Just tryied to start it with the gas switch on the line in the off position(no gas to the carb).
It STARTED FINE and then opened the gas and runing good but after 30 seconds on idle it dies.

Did you try it in the off position? It could be labeled wrong

 

[Chainlube]

Just tryied to start it with the gas switch on the line in the off position(no gas to the carb).
It STARTED FINE and then opened the gas and runing good but after 30 seconds on idle it dies.

If the on/off lever is inline with the fuel tubing, then the fuel is on, if it forms a "T" then it's off.

 

[Bikemovile]

Did you try it in the off position? It could be labeled wrong

I'm sure its okey. May be the float level on the carb just flooding the engine?
One hour ago I was almost sure it was problem with compresion but now dont know what to think at all LoL. It its pranking me.
This can be normal on a brand new engine?

 

[Bikemovile]

Thanks for your messages!
The switch is okey.
From now on I'm shutting the engine switching off the gas, rev it high 3 secs and then clutch-killing it.
Sorry if my english is hard to understand hahah