Hello all!

New member....first post. I just recently bought a 2005 Yamoto 150cc for my 11-year old son. I bought it from a trustworthy co-worker who told me it had been sitting for almost 6 months and only has about 40 hours on it. It starts and runs fine but smokes quite a bit. The previous owner states that it still had the original oil in it so I decided to change it. I drained the oil and flushed it with kerosene and re-filled with about a quart of 15w-40w. However, before I drained it, I noticed that the oil level was extremely low (didn't even show on the dipstick). Do you think damage to the rings has already been done or could this be a symptom of the bike sitting for so long and just needs to be run for a while?

Thanks in advance,

 

IMO::Smoking is either one of 2 things...
Wore piston/rings or valve seals.
A compression test may point you in the right direction.
I feel it's the valve seals.