today i went to look at a 2004 yz125 that i was interested in.and wen the person went to turn the bike on it starts right up then when it idles i heard a knocking/vibrating noise coming from the head of the motor or the left side engine like were the crank is. it sounds like it were a bearing inside the engine that were broken. i went to put my hand on the cylinder and its really shaky like it moves sideways like the rod were movin sideways what do u think it would be the guy said it was normal and thats how he bought it so is that normal?i need some help.

 

No bike/quad comes brand new with a knocking sound in the motor... Should not be normal nor should a 125cc motor shake that bad. Now maybe if it was a hemi.. then it could shake. =0 lol

 

the bike wasn't brand new, even though it looked it.

 

I got a 04 YFZ with all stock motor parts sept pipe filter. With over 700 hours on it and it dont knock shake or make any noises a brand new motor dont make. The bike being 2 years old should not knock unless it was not took care of as this one sounds to be. It could be just a rare lil fault in a part. But it isnt natural.

 

those 2 stroke motors usually make a weird noise and shake...

 

Yea man that doesnt sound normal, I had a 1998 yz125 and had it for over a year and no vibrations what so ever. Does the noise get louder when the engine is reved? Maybe you can use that as a bargaining tool to get the price down saying that there could be some damage. Good Luck

 

if u rev it u dont here it only when it idles