Scooterotica

Remember a while back,there were kits on the market that were 200cc S.I.L barrels,lathed down,and the stud holes drilled out,so they would fit the small block engines?,well,i picked a used one up,cleaned it up,and fitted it to Mrs Kevspeeds scoot.
It does the business,but clatters a bit,as in sounds like piston slap!.
Now,before fitting,i did the piston/bore clearance check,and all read within tolerance,so im wondering,if the clattering is an unfortunate product of the thinner spigot or am i looking at something more serious?
Anybody else run one of these kits and experienced the same clattering sound?

have you stripped the engine yet ?

If it were me I think I would try removing the spark plug and the alternator cowl and spinning the engine up with a drill. You'll need a drill/socket adaptor set like this https://youtu.be/f0d6NMmU6v0

Without the engine running it should be a lot easier to listen to and isolate the clattering sound .

Try using a stethoscope or a wooden dowel or even a large screwdriver to your ear to pin point the sound