hollows

Haha thats the worst part of the story it was just a spark plug.. changing it would have taken me 2 minutes but for god knows what reason i decided to take it in a shop:

Well you can be correct..I did buy it from another guy who worked on it for years. And that can explain why it blew out and didn't cause any damage.. well thanks for the post and ill take it to another shop just to be sure of which plug should i use

They sad that the plug was a bit longer but that shouldn't be the problem couse they did that on another aerox and nothing happened .. I just know that they screwed up but can't take the blame. Thanks god that the piston or the cylinder head are not damaged couse as i see it i would have payed for the new parts.

Well i can't feel any difference on acceleration or on top speed.And i think the spark plug hit the bottom of the seat so that can be the noise i heard.With the old spark plug the sound is the same as it was before.I'm just worried couse if the piston is damaged i would need to spend alot of money to have it changed.I will visit the shop again be sure of that haha:) thx for the replay

I have a 70cc tuned yamaha aerox. Everything was running fine till few days back when i decided to take it in a shop nearby to have the spark plug changed.They called my and sad that they've putted a new plug and i thought that was it. My scooter worked just fine with the new spark plug when yesterday i was driving around 80kmh and i heard a bang so i pulled over...The spark plug was blown out but there wasnt much damage on it just a tiny dent on the bottom...so i guess the piston must have hit it couse when i compared it with the stock one it was much longer and i have no idea how they overlooked that...I've put my spare plug and my scooter is running fine once again but im worried that the piston might be damaged... is it a serious problem or it could run as good as it was before?