Prepare to be inundated with replies to this post. Saito are good engines as are OS as are many others. Don't be put off by plain bearings as opposed to ball bearings, many manufacturesrs make both and for most applications you won't notice the difference.

Engines with twin needle carbs as opposed to air bleed are more set and forget. What ever you decide on follow the manufacturers instructions about running in and what ever you do err on the side of too rich rather than to lean.

To put the cat among the pigeons I'm sure someone will tell you that MDS stands for "Mulitple Dead Stick".

Cheers,

Colin