Engine year with no numbers 86/87?? Need to buy parts..

[tracks]

Need some help here, buy the looks of things I need to do a top end rebuild on my KX250. I picked the bike up very cheap in a bran clearance, its had a hard life as you can see - there are no engine numbers apart from the images below!
 
I have split the engine and got the piston off but there is no part numbers on it either, I have been looking around and I'm pretty sure its an 86 frame.

I have measured the piston BORE and CYLINDER - they are both within a few hundredths of a mm to 70mm
 
According to this http://www.oem-cycle.com/KAWASAKIKX250BIKEID.shtml%C2%A0
PISTON STD BORE AND STROKE - 70MM BORE X 64.9 STROKE
 
It would suggest I do have an 86 engine
 
Can anyone confirm what the 87 stamped number means? Or is it 78? I didn't want to start ordering parts for the wrong year!

Let me know if the images don't work, thanks in adv.






 

[Foxx4Beaver]

it's definitely an 86 frame.
there isn't any numbers on the top of the right(clutch side) engine case?...they should be located here...


if not, could be someone filed em off for some peculiar reason

[tracks]

No no numbers, sorry to the original owner probably back in the 90's!? Would have probably been weighed in for scrap if I hadn't taken the project on!

Yer 86 frame but the later carb throws a spanner in there, but with the bore size it must be an 86 engine, 86/87 is the cross over to the smaller piston bore.

[Foxx4Beaver]

the member Sandblaster should be able to tell you exactly what you have there...he's the man when it comes to deciphering frame/engine/carb VIN #'s and years.
you can either PM him, or I'm sure he'll chime in a little later.

[sandblaster]

If I had to take a guess I'd say a 86.
Here's why.
84 had no exhaust valves and used a different cylinder altogether so I know it's 85 or newer.
86 and older because the left engine case has 78  as part of the casting. 87 and newer didn't have it.
So now we are either 85 or 86.
86 because it's the only year kx250 with a 71 as part of the casting on the right side of the cylinder.
That's my prognostication for the morning 

[tracks]

Thanks for the info