it looks just like the normal one except its perfectly flat. Its a pretty tedious process because even when you think its good its not. You have to twist and turn the cylinder with the reed block/intake on top to make sure it really is flat (looking into the light).
In all honesty it doesn't have to be perfect if you take proper precautions. Mine was all nice, no leaks but it still warps the cylinder a tad when you torque it all down. I simply sanded my piston down so there is zero friction on the intake bridge of the cylinder. Sure the piston my be a little "loose", but I'd rather it be loose than too tight. Intake leaks are bad, as are warped cylinders.
Mr. Smith, are you running mikuni now or future thoughts?? Still with points? I think my polini has run a 102 or 106 for the past year or so, pretty sure 102 but I'm not 100% on that. When I was running the mikuni on the derbi (w/ polini) I had a leak somewhere, but I ran something stupid like a 220 or so, but eventually settled around 185. It was pretty quick once everything worked almost right.
K, too much writing. Gabe, one day, hopefully sooner than later.