What is the best way to get the same finish on the aluminum wheel hubs? I don't think they were highly polished. What is a good clear coating? Thanks Stan

Show us some pictures 

Lots of opinions and methods. Here is a link to one in the forum
www.yamaha-enduros.com/index.php/forums/...ning-aluminum#120624
 

When I did my DT3 I polished the aluminum to a scratch free shine. I started with #320 and worked through the grits to #1500. I used a bench buffer with orange jeweler's rouge then I finished up by hand with Mother's metal polish. After that I put very fine scratches in the proper direction with a gray scotch brite pad ( finer than the red ones) to leave a nice satin finish. I then clear coated with engine clear. I had a NOS sprocket cover that I didn't want to mess with and the covers that I polished matched perfectly. I accidentally posted this on the last page of the link posted by adguy2112, oops...long day.
Cheers

The original hubs on a '68 were sand cast and will have some imperfections.  Be prepared to be finding them and living with them.  Usually small sand cast air pocket holes.  Also, they were never shiny.  Think of them as having a dull luster.
I've done a number of these and I'll share my method.
Wet sanding:  I cannot tell you how course a grit you'll need to start with but don't be surprised if you end up using 80 grit to get going.  Patience through each level of sanding is paramount and keep at it up to 1000 grit.  Remember - not shiny!  At 1000 grit - if done right -  will probably be a bit too shiny, But the next step - coating - will dull them just the right amount.
Protection:  If you want these to hold up to dirt, grime, grease, harsh cleansing detergents and oxidation through the years you will need a quality coating.
Here's my choice....  www.eastwood.com/exoarmour.html.
You will get what you pay for.  If you choose to put a $6 rattlecan clearcoat on them I can assure you that you'll be doing your project all over again someday in the not too far off future.  And if you haven't hand sanded aluminum (or any metal) yet, you'll soon see why you want to protect your work as best you can.... unless you work isn't worth protecting  lol    

I do like the finish you have right there.. But the daunting task of un-lacing and re-lacing a spoked wheel... THAT scares the S%&T out of me.. 
Sneezles61

.

Here's "THEE" correct factory finish for an early DT1 hub . . . Not sure of this particular hubs part number though
 . . . but it might have a shinier finish then what the 68 model had ???

 

Off the point of this thread, but should engine covers have a coating put on after polishing? (mine is a DT3)

Absolutely!  Naturally, they're subject to rubbing from your footwear in addition to the peppering they receive from pebbles, dirt, rocks etc. as well as gas and/or oil spills - but the better a coating you use the longer they'll remain protected.

I’m in the process of finishing my ‘68 hubs to a factory finish.  You can see on the attached photo the sand cast pitting mentioned by RT1. I started with Vapor Blasting and then I like to use the 3M foam backed sanding pads as they adapt to the contours.  They offer 5 different grit levels depending on the finish your looking for.  These were sanded with the Very Fine pad (500/600 grit) and then hit with a fine solid brass wire wheel on my drill press to give a little sheen which I will probably will knock down a bit.