Anyone willing to give me some suggestions about 2-stroke engine

Is it a platinum spark plug? If so they're more difficult to get a good spark out of than traditional copper plugs and require a beefier coil.

>>1064396

Spark in open air doesn't mean anything on the plug. A good spark must be able to jump a 1/4" gap in open air to be able to spark when the cylinder is at 110+ psi compression.

>engine chokes alot when trying to get it on higher revs

Your carb high speed needle is not set properly or you changed the amount of oil in your fuel mixture. The carb needs to be tuned for your particular mixture, also small chinese carbs like this are usually shit and not properly designed.

>>1064413
Copper (i think). But thing is, everything was working flawlessly before this "something" happened, i haven't changed anything - i still use old spark plug, only a little bit more bent.

>>1064417
I haven't changed anything. Carb needle is in the same place, amount of oil hasn't changed. Everything was working fine until "something" happened.


Shit, i forgot to mention thing that may be important: couple hours before engine has stopped working, i bent my muffler over some rock. There was rather large gap between muffler and engine block and it was very loud, later i bent it back and used some muffler paste to seal everything up nicely. Muffler and engine block connection is airtight now, but it wasn't for some time and i did some kilometers with this muffler gap.

I don't think anything bad has happened though, i opened cylinder head and everything was looking fine.

>>1064419
>I haven't changed anything

Regardless it's not set properly for whatever conditions the engine is running in now.

>>1064441
I tried to set up needle in different positions, nothing changed.

I think i'll try to replace the coil thingie. Just a random guess based on spark that might be not big enough.

>>1064396
Those cheap chinese motors don't usually come with gas filters and all the crap you pour into the gas tank goes into the carburetor, I had the same problem with a mini-bike, before doing any expensive thing just remove the bottom cover of the carburator, you shall see a brass screwy thing, that is called a jet, unscrew it and check for obstructions, clean, screw again and screw the bottom cover again.
A blocked jet will cause problems at higher revs, making the engine to "suffocate" and struggle to keep running.

>>1064628
I do have gas filter, and i checked carb before doing anything else. Carb (and little hole in jet thingie) is fine, i'm pretty much sure about that.

>Engine wasn't working at all until i bent spark plug leg a little bit closer to the core
>Now it works in retarded manner, igniting every second cycle or so

Check "CDI/Coil" connections also magneto connections.

https://www.youtube.com/watch?v=Nd2G9FB1nJk

File: 550px-Arbeitsweise_Zweitakt.gif (204KB, 550x148px) Image search: [Google]

204KB, 550x148px

First thing to do when diagnosing a two stroke engine is to do a compression test. That'll tell you if your piston fits the bore correctly and there has been no damage when the engine ran lean.

The reason I say it ran lean is because of the problem with the exhaust. Two strokes are utterly dependant on their exhaust pipes - and specifically the expansion chamber - to force air/fuel mixture back into the combustion chamber. Pic very much related. So if that stopped happening due to the exhaust problem, you ran the engine lean. A lean mix can cause severe damage to the piston. So do a compression test, and if it's less than 120psi then pull the head and barrel off to inspect for damage.

Suspect carb issue. Remove and clean.

It was the coil thingie, i replaced it and it runs like a dream. Thanks for all of your suggestions, problem is solved.

>>1064396
The boys at /o/ might be more help

>>1064419
Muffler timing on 2 strokes is very important, if it isn't exactly the same shape it was before you bent it, it is very likely that is your problem