Since my ZA50 (pronounced ZAH50, like short for Pizza, as in "hey lets order us som 'roni 'za") refused to roll backwards, that was nice enough to allow me to realize it was shimmed incorrectly. I have not the factory tools to measure, and even though they work very well, it isn't really a measurement so much as it is like a mechanical version of putting your fingers apart from each other on the back of a frame you want to hang up, and then moving them to the wall to make pencil marks. So with the advice of Mr. Mike Mike Naz, I went and purchased myself a machienst square, which was about $12, and a new battery for the shops digital calipers, which was $6. Oddly enough. So using the straigt edge, I was able to accurately measure the distance from the case, including the gasket, to the inner bearing race, as seen here.
Credit goes to Dean, who had to take this picture twice as the first time I was incorrectly measuring the other bearing by mistake. Then using the straight edge, it gets a little trickier to measure the gear of the bellhousing, but not too difficult once you get the hang of it. Take several measurements until you can get a consistant reading.
Take the two readings, subtract the bellhousing from the case measurement, and you have your end play float. Mine was .6mm with no shims. The factory specs are .05 - .25mm, which is as Chuck suggested, about the thickness of a Dr. Pepper can. Since I want to stay away from aluminum in this engine. The shim that I had in there was .6mm, and to land right in the middle of the float range, I wanted a .3mm shim. Since there were no local places that I could think of that might cough up the shim, I attempted to sand my shim down .3mm. All I really did was end up sanding my finger tips off, at which point I gave up and used power tools, effectively ruining the shim. That's fine, McMastercarr has the exact shim I want in a box of 25 at .1mm thickness for only $5. So I can stack a few here and there to get the height correct and be happily riding doubles in no time. Naz also suggested that I remeasure the float after a few miles since the bushing he machined for me might settle in a bit. No problemo!
I was running a Malossi red and black filter, but that got quickly soaked with the deluge of blowback that spews out of the carb. So I ran it without a filter last night, and it runs good. New filter on it today, the UNI is a faithful and easy breathing standby. I love feeling the power through first gear, when the pipe comes on it starts to pull hard and won't shift until you let up on the throttle.
Then you get a small lul in second gear before you get back on the pipe which seems to be about the perfect cruising speed. 
What a sweet sounding exhaust, too by the way. I love that Homoet sound. For no particular reason, here is Matt Smith, pretending to have fallen from the sky. 
