I've heard claims that fairing lowers may direct more air to the engine, but not the fairing by itself. I've never had the lowers. Vetter used to make a lot of claims for the Windjammers, but I've never heard that one.
Been building and flying machines for a number of years. Studied a fair bit about aerodynamics, too. The vetter doesn't block the wind, it redirects it. just look at the area under the headlight of the vetter.
Vetter did a fair bit of aerodynamic testing. But, I don't know of any claims by them for increased cooling. Still an air cooled motor's temperature is determined by the volume of air accepting heat from the fins. (I've done thermodynamic engineering, too.) Increasing the air volume, increases the cooling capability.
Like any investigation, it would be interesting to see if the fairing directs more air to the engine. But I doubt the fairing has much to do with the longevity of this particular engine. As I've said many times over the years, I knew of a couple and heard of more 750s that went over 150K back when the bikes were more current. The two I knew of didn't wear fairings. So my bike isn't unique by a long shot. Much of the time the reason the engines were torn down was because oil leaks got so bad that the owners didn't want to put up with it anymore, not because of any particular mechanical problem. As we all know, the 750 will leak under the pucks under the cam, and through the head and base gaskets. In 1996 at 52,000 miles, mine was weeping badly from the head and base gaskets. I couldn't go far without my pant legs getting wet with oil. I pulled the motor and re-torqued the head. I encountered a lot skepticism that it would take care of the problem, but it did. The weeping stopped completely.
Then in 2002 at 82,000 miles, the engine was leaking again. This time it was from the cam holder seals. I pulled the engine to replace those (the old ones were hard as rocks) and took the opportunity to re-torque the head again, though there was no weeping from head or base gaskets at that time. After that the engine was oil tight again. Then in 2009, I was in a Walmart and saw Mobil 1 motorcycle oil on sale for less than I was paying for Spectro at the time. I bought it on a whim and put it in the 750 at the next change at 116,000 miles. Within 1000 miles, the engine was lightly weeping oil on the cooling fins. I ran the Mobil 1 for 4000 miles and changed it out, back to Spectro. The engine continued to intermittently weep oil, but as time went on it became less. The weeping still comes and goes, but it isn't enough to worry about. It takes about 500 miles for it to become evident on a couple of fins, always on the left side. Over the 1300 miles I put on it for the relay a couple of weeks ago, it hardly weeped at all. That time back in 2009 is the only time I've run full synthetic in the bike. I did run HP4 in it from 1994-1998 before switching over to Spectro.
