Dong Fang DF 250 RTB Bobber Information

[axa]

yeah probably will open it up just to see, I would like to know for sure, and I will ask this guy.Thanks Bar.

woh woh, slow down guys! just jumping and looking into entire engines is a bit hasty. i know the feeling but relax.

the fact that you got it going after you heard the noise, Occam's razor and my intimate knowledge about a 167fmm's combustion environment tells me that there is less of a chance that there is bad damage.
my 2000 mile diagnosis says you have a blow head gasket.
that can be noticed if trying to start it, and you see or feel gush of air somewhere between the head and cylinder body.

been there done this, i carry a spare as standard procedure...
6$ on ebay.

of course its hard to diagnose over the internet so:
pull off the head cover.
pull off the head. 4 bolts.
if im right you will see a torn up gasket.

Now if there isn't any damage to the mating surface place in the new one.
if it were me id resurface and use nothing, but you might want to dab a bit of rtv silicone around the same places it was used when you pull it off.
put it back, i think 22 ft lb for the head bolts. 60 in pb for the head cover.
you will likely need to adjust the valve clearance after removing the head.
i use .04 in, .06 out.

there... bikes running again for 6$

if you had open it up and your head looks like this:
https://drive.google.com/open?id=0B-...1NvM1ZPOThlOFU
or if your piston looks like this:
https://drive.google.com/open?id=0B-...nd1MlV2b0ZuTU0

then that's a different story, but you would not have gotten its started again if it had...

you can check for this sort of damage by taking out the spark plug and seeing if it looks like this:
https://drive.google.com/open?id=0B-...3BNZDBCY0hKNUU

if it does unfortunately the other damage is fairly likely.

take pictures