Hi, first off i need to say i know very little about engines but hopefully i can explain the problem.

My atv randomly stopped starting with the electric starter and i could only bump start it and some time later it wouldnt even start like that.
Started Googeling and most common problems was sparkplugs so i changed both and i also changed the ignition coils and spark plug caps since they fell apart once i took them off.

Now it starts again but still only if i bump start it and electic starter will only work once the bike is really hot.

The carb have always been leaking a little but from what i saw it was just the float or float needle, borrowed another carb from a friend to check if that was the problem it still wouldnt start.

It idles horrible and started to sound almost like a chainsaw.

I got it for very cheap so it's not the end of the world if it's something major broken.
from what i can tell its a 253fmm engine.

Took 2 videos with my phone, recording sound is not good but its the best i could do, maybe someone can hear something.

https://streamable.com/6dls3
https://streamable.com/imtfk

 

That engine looks exactly like a Quadzilla from the video. Can't make out any noise, but the most common problem with a bike that will only tow start is the valve clearances or other reason for low compression such as burnt valve or worn rings, but it would then smoke badly.

 

i would start by checking valve clearances..

 

Forgot to come back and give an update but it seems valve clearance was indeed the problem, followed some youtube videos on how to do it and now it runs again.

Thank you both very much!!

 

good to hear