Kama Sutra - the big windshield position?

[Fred W]

OK so last year sometime I bought a used V-Stream windshield (from Fairlaner here on the forum) for my 1st Gen . As those of you that have one of these already know, them are one big hunk o' plastic. Now I'm 6'2 with a 32" inseam (read: tall in body) and have Heli Bar backs so I already had some home made 1/2" spacers (tuning blocks) installed under the W frame to make the stock shield tip back toward me a little.

I found that the V-stream shield does block a lot of wind from the upper body, and so is quite useful for cold weather riding, but I experienced a good deal of backpressure and buffeting even if the shield was barely raised. I've never tried it without the 1/2" spacers, but would have to assume that a more vertical angle would only make everything worser. So thinking along these same lines (yes, I do think sometimes) I reasoned, "Hey, I wonder what that shield would be like if I tipped it even further back?" and so I snagged some 1" long plastic spacers and longer 6mm screws from the local true value hardware store for e'sperimentin'. Here's what I found:

The 1" spacers tip the top of the shield back a considerable amount in all positions and also open up a larger gap at the bottom edge.

This is a good thing IMO since the Heli risers tip me back too. It makes it so that in the fully down position I get a nice clean air blast on my upper shoulders, which is kinda welcome on warmer days. Here's a pic with the shield fully down:

As the shield is raised something really nice happens: There is very little tubulence off the top of the shield. My theory is that this is because of the larger space between the fairing and the lower portion of the shield. You can actually feel a good amount of air traveling up the back side of the shield. I find that with the shield about 1/2 way up I have excellent visability over the top and get a nice laminar air stream at about mid face shield. Here's what it looks like in the middle positions. Note the good sized gap at the bottom edge

There is a downside to the spacers though. If I raise the shield fully the increased angle of the upper bracket causes it to contact with the top of the slots in the nose faring. You can see where the obstruction is on this close-up, and also see the bottom of the right hand spacer.

I considered enlarging the slots in the nose piece, but have found that, even if I do raise the shield fully, I am unable to get the airstream completely over my head anyway and so still get some minor buffeting up top, which I prefer not to experience. So it looks like I will try running with the 1" spacers and the shield about 1/2 way raised for a while.

I've also made a home-made laminar lip like extension dealio that I can velcro attach to the top of the shield for when it gets truly frigid. You can see the velcro strips on the shield pictures from when I was playing around with that. With that on and the 1/2" spacers back in I can actually get fully behind the shield and completely hide from the wind. Not sure I'll like riding looking through the windshield though...

Just a few more options for those in search of the holy grail of shields. Oh, and I guess I'm still looking

 

[painman]

Fred glad you have gained some ground in your search for that special window for your FJR. So with the extra opening on the bottom of the shield more air in the bottom allows for less air on top. So those of us with the Gen II bike the extra opening already on the bottom of our window will or should perform in a similar fashion. I really like the looks of the V-Stream and hope to get one soon. Also you didn't mention unless I missed it, if the back-pressure was relieved any by doing the mod you described. Was it helpful in that area Fred? Great post and keep up the good work. PM. <><

 

[jwilly]

Fred,

Thanks for sharing your research. I'm going to be adding a Vstream for winter and long trips.

JW

 

[Grumpy]

Actually if you're using "wings", the backpressure goes away and is replaced by cool air funeled in by the wings......sweet!

jim

 

[Fred W]

Fred glad you have gained some ground in your search for that special window for your FJR. So with the extra opening on the bottom of the shield more air in the bottom allows for less air on top. So those of us with the Gen II bike the extra opening already on the bottom of our window will or should perform in a similar fashion. I really like the looks of the V-Stream and hope to get one soon. Also you didn't mention unless I missed it, if the back-pressure was relieved any by doing the mod you described. Was it helpful in that area Fred? Great post and keep up the good work. PM. <><

Yes!! The extra gap at the bottom does reduce both buffeting at the top and backpressure. And I think it is more than one might expect for the amount of added gap.

Also, one point I forgot to mention is, the air that does go through the gap at the bottom does NOT blow back on the rider. It travels up the back side of the shield and eventually joins up with the normal blast off the top of the shield coming from the front side. I expect that the reason for this is that the vacuum on the backside of the shield must be progressively high traveling upwards perhaps due to the tilted aspect of the shield.

Anyway, it seems to work that way.

 

[Fred W]

Actually if you're using "wings", the backpressure goes away and is replaced by cool air funeled in by the wings......sweet!jim

Ques que ce "wings"?

They don't exist without pictures, you know...

 

[Toecutter]

I would caution against the plastic spacers. BTDT, and one morning the bolts snapped at 80 mph, leaving me with a screen folded down on top of my bars for the ten mile ride home in the frigid tule fog. Lucky I was close to home. If I wanted that much rake, I would stack two sets of Skyways spacers. YMMV

 

[Fred W]

I would caution against the plastic spacers. BTDT, and one morning the bolts snapped at 80 mph, leaving me with a screen folded down on top of my bars for the ten mile ride home in the frigid tule fog. Lucky I was close to home. If I wanted that much rake, I would stack two sets of Skyways spacers. YMMV

Not sure how that happened, unless your plastic spacers were something different than what I used. In mine the 6mm screws go all the way through the spacers threading into the metal bracket. So to "snap off" would require breaking off the two 6mm steel screws. The plastic pieces are only, well... spacers. Like really thick washers.

OK, I give up. Here's a picture of the spacers, both 1" and 1/2" variety:

And here's the 1" longer spacers installed:

I really don't see how these would just break off, unless maybe you were flexing the bolts somehow and they fatigued?

Also, Skyways spacers don't show any close ups. How are they any different?

 

[Toecutter]

I really don't see how these would just break off, unless maybe you were flexing the bolts somehow and they fatigued?

Bingo! My setup (which looked exactly like yours) worked great for about four months, then....

Also, Skyways spacers don't show any close ups. How are they any different?

The spacers are machined from stainless steel.

 

[Fred W]

I really don't see how these would just break off, unless maybe you were flexing the bolts somehow and they fatigued?

Bingo! My setup (which looked exactly like yours) worked great for about four months, then....

Also, Skyways spacers don't show any close ups. How are they any different?

The spacers are machined from stainless steel.

OK, so you think the plastic allows the bolts to flex and fatigue and skyway's blocks being solid stainless don't?

Does anyone have a close-up picture of the Skyway blocks?

edit: I see the Skyway spacers on the first page of the link you already provided.

They look just like the plastic ones, only metal and a bit thicker/ larger in diameter.

Might be worth buying... or duplicating.

But if they are only 1/2" thick I can say from experience that is not enough tilt-age for the V-stream barn doors. Maybe a combination of 1/2" spacers and some additional vent holes would be the ticket.