Hi Guys,
I have some photos attached.  I have my 71 DT250 float arm parallel to the bowl, which leaves it at the Service Manual measurement "A" at 12.5mm. 
The manual specifies 15.8mm, so if I bend the tab, my float arm will tilt down, like the orange line I drew.  Is that correct, or is it supposed to be parallel to the bowl?

Also, is there a good source for the little caps that go on the tops of the float rods?  Mine are so hard they will not go back on.  
Thanks,
Doug
   

I could be wrong and often am, but the manual shows the carb upside down, so a higher "A" will lower the fuel level and therefore your line would be flipped along the horizonal axis.  Also, if your needle has a spring dohicky within it, then the measurement is made when the tab on the float that you adjusts is just touching the needle titty without compressing the spring under said titty.

those little bead buggers are there I think to help you assemble the carb, none of mine have them and no issue.

It’s correct as it is…
a

Carb body surface is shown wrong in your manual pic. Should be at the gasket & can allow a mm or so for the gasket. Looks good as it is, parallel. That's how i do it without measuring--i think--been a while!!.

Yamaha changed the measuring method...  I think it was in the early days they measured from Jet Setter down...  then later from gasket surface up.

Float level specs are often wrong and inconsistent in Yamaha literature...  Parallel to gasket surface is what I have done for years after figuring this out. 

And yes, caps are not needed...  new Mikuni carb I bought didn't even come with them anymore. 

Always something to learn. & i'm still learning haha. Better look at my manual & see what it shows out of curiosity. But parallel always looks good. My little caps have long gone as by memory wouldn't go back on & don't want to bend the float pins trying too hard.