Well, I do "style" my own hair in the garage with a set of clippers! 

 

GR8Al... I tried it on top on my RT2 and I still couldn't adjust my rear shocks... I'll spin the other way shortly... 
And for what its worth.. seems redundant to cut hair as it keeps growing... Well, mine does any ways... 
Sneezles61

I'm going to leave it in the under mounted position and continue enjoying the bike and my maintenance technician career. I don't think I'd be a good hair stylist. I've been buzzing my head for years which doesn't take a whole lot of technique. 

The RT3's came mounted on top. The RT2's were on the lower side. My Dad purchased a brand new RT3 in late 1973 from a local Yamaha dealer. The lever is on top on that bike. I ended up finding a few rare pictures of my dads bike when he 1st brought it home. I have owned 3 RT3 including a low mileage one owner bike. All had the levers on top. When i restored the RT3 that 1971DT250 now owns i did a lot of research on this. Every picture of a new bike, brochures, manuals and even a Yamaha poster from back then shows the lever on top so i installed it on top on that bike.
 Kaplans cycles has had a few good RT3's over the years including one right now. The levers are all on TOP. 
It's not a coincidence that all these bikes the lever is on top. It's highly unlikely dealerships installed the levers on top by mistake or all RT3 owners decided they wanted there Decompession levers on top?

Is it right or wrong? No. Does it really make a difference? No. Mount it where you like it. I so happen to like it on top out of the way! Maybe Yamaha decided the same? If i were to do a concours restoration on a RT3 today,  it would go on top.

Here is a link to Kaplans bike. His descriptions are a little off the wall but they do bring a lot of vintage bikes out of peoples  collections and storage.


 

LOL I sure wouldn’t use any Kaplan bike as an example for anything about how a bike should be put together. 

Who needs oil threads? 

I'm not taking sides but Yamaha pictures, manuals, and diagrams are rife with errors and differences from actual models...  Dealers assembled bikes incorrectly and many "expert" restorations are not correct. 

Not just with Yamaha...  My first new bike, a Husqvarna 250CR, came with white number plates and the front brake on the left side.  I have personal experience and factory literature that proves these two details.  Yet I've seen a few very expensive professional restorations that have used the color-coded number plates (green for 250) and have the front brake on the right.  I've spoken to a couple of those gentlemen and they are adamant that they are correct when I know for a fact those are details that changed from 75 to 76.

It's your bike, put it together the way you want to. 

Just make sure you only use Brand X oil because it's the BEST and anything else will ruin your bike!