Something that most people rarely try is go to a brick and mortar Yamaha dealer...  the older smaller ones are better.  They can run a "parts search" and find parts at other dealers parts rooms across the US.  The online only checks the Yamaha factory warehouses.  You'll probably have to pay for shipping but I've found a couple parts that way.

Try looking for 6v VW instrument light bulbs at a VW parts place or ebay..  I think they are the same.  Somewhere I have a generic part number but not sure where right now.

Once again Mark, thanks for your help. Will give those a try.

If you're happy to go with 6v 3w, then there are loads on fleabay. Stick to suppliers in the US.

Thanks. I did a Google search and found this on Crowley Marine:

BULB, MTR 6V1CP BA9S 122-83516-10-XX
There is a newer version of this part: 122-83516-10-00
$2.28

I just remembered I got the last ones off the shelf at Autozone or O'Reillys.  They had them right out on the floor in the bulb section.

just a quick point...rocky mountain does list parts that are NOT available.  ive gotten stuck a couple times by that.  page may say parts ship in 7-14 days, and they might but that could say the manufacturer has discontinued them.

Yes, that can happen occasionally if Yamaha shows them as available but they aren't.  Very little in life is absolutely guaranteed.  The difference is several other sites will take your money for parts that are definitely not available. 

In my experience, Rocky Mountain is good with communicating and refunding promptly if it does happen.  I scored a set of new (and very hard to find even used!) DT50 side covers after RM contacted me and said Yamaha had them overseas someplace and it would be a few weeks.  I said I'd wait and they did arrive. 

+1 on Rocky Mountain, I’ve had good experiences with them on at least a couple dozen transactions, fair prices, lower on some items and higher on some items from other competitors but I usually receive my order within a week and free shipping if your order is over $75.00