Gen1 Windscreen tuning block lessons learned

Everything you've heard on how well tuning blocks work for your windscreen is correct! Do it! It's awesome.

I've heard and read all about tuning blocks etc, on the forum. Never really seen how they work or where they went by showing it in pix. I was at Johnny80's tech day last month, and I looked at his tuning blocks on his Gen2 and thought I'm not sure my mechanism is the same, or the blocks go in the same spot on the windscreen rail. Well they do. Never having the rail off the windscreen mechanism, I didn't know, but it's similar, just shaped different.

The tuning block or spacer really (skyway calls them tuning blocks), goes between the bracket of the windscreen, Stay2 (the parts with the windscreen nuts in them), and the actuating arm (Stay leg Shield) in the middle. I got some rough dimensions and advice from Johnny80's. His V-Stream windscreen with 1/2 inch spacers hit the fairing cowling when riding due to buffeting. He had a 1/4 inch gap when standing still, but when riding it would hit or rub occasionally and eventually wore some paint down.

I originally used some washers stacked about .307 inches high, and it worked great! I then had two sets of spacers made, one set 3/8 inch the other set 1/2 inch. I tried the 1/2 inch worked OK. Got tons of air and no buffeting, no windscreen rubbing, but the arm mechanism hit my cowling and moved my cowling and dash down, a lot, almost 1/16 inch. I took it off and put on the 3/8 inch spacers. Works perfect! No interference although very close see pix. Works awesome, great air with no buffeting.

Here's where the spacers go. These are the 3/8 inch (gold) spacers installed.



This shows how close it was. I couldn't get a great pic, but it's really bloody close.





Here's the 1/2 inch spacers and screws I bought (steel and stainless steel, why not). The stock bolt on the far right is 16mm, I also purchased (right to left) 25mm, 30mm(not shown, they're installed), and 35mm. The 30mm bolts you see in the other pix don't come close to hitting the cowling but does stick out a couple threads farther then stock.

the 08's and on are different (they suck) and the spacers will not work.

R

Fairlaner said:

the 08's and on are different (they suck) and the spacers will not work.
R

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Thanks for you old spacers my friend. They are working great on my 07.

<hijack>

I've got some spacers from my '04 that I'm not using. If a local wants to have them they can come pick them up. I'm shorter and like the stock arrangement.

<hijack>

I originally went with some spacers for quite a while. The reason that Skyway calls them "tuning blocks" is because that is what Rifle calls theirs. I believe that Rifle originated the idea of tipping the windshield back, and they come with their 1st gen FJR windshields. I now own two Rifle windshields, one "sport" and one larger "Touring", and both came with tuning blocks. The tuning blocks look like this:





You'll notice something special about these blocks. In addition to the small vertical offset (L-R on 2nd pic), which helps make up for some of the lost height of tipping the shield back, there is an angle between to the 2 surfaces that bolt to the windshield W bracket and to the base drive bracket. I believe this is pretty important as the two brackets do not want to remain parrallel when you space them apart. This means there is lateral loading (bending force) of the two (longer) screws. Some people running hard plastic spacers have had these screws fail over time, at which time the windshield flips back at you. Having that happen at the wrong time could be disastrous.

Using metal spacers, as you have, should reduce the flexing of the bolts, and minimize the metal fatigue, but the lateral loading of the bolts will still be present somewhat.

If somebody wanted to try to duplicate the Rifle tuning block design (and make a bunch of them), I have an extra block that they could borrow or buy. The only problem I foresee is the screws are threaded into the tuning blocks, so these would have to be made of steel or some hard metal, not aluminum. Not sure if anyone wants to take on a project that big. I don't believe that you can buy these from Rifle without their windshields, but am not positive. May be worth pursuing.

Awesome post Fred, thanks. We now have some history to this and the real tuning blocks.

Skyway's are truly spacers per his website/photos. I've never seen the ones you posted, that is cool.

Has anyone had a mechanical break or failure of the windscreen mechanisms due to the tuning block or spacers?

FJRBluesman said:

Has anyone had a mechanical break or failure of the windscreen mechanisms due to the tuning block or spacers?

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I had them on my '04 and on the '05. Many miles, some high-speed desert crossings with no issues.

Some people did not use stainless screws and the longer screws through the spacers corroded/rusted and broke. Not many but I remember reading a couple of posts.

Rifle will not sell their "tuning block" as a separate item. I wonder if copying their design could be grounds for a lawyer's letter to cease and desist?

Ian came up with the spacers because several of us had been using homemade spacers. IIRC, I stacked 2 SAE 5/8 nuts. He produced his spacers as a cleaner option.

I've had the Skyway spacers for about a year now on an '03. They work well and I'm pleased; it's a simple mod and makes a noticeable improvement (not huge, but enough to make a difference for me).

I like the looks as well as the functionality. The w/s (a Yamaha touring screen) doesn't stand up so vertical, so it not only looks better but reduces backdraft.

My screws are stainless steel and don't appear to have any rust at this point.

So far, so good. :thumbsup:

madmike2 said:

FJRBluesman said:

Has anyone had a mechanical break or failure of the windscreen mechanisms due to the tuning block or spacers?

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Some people did not use stainless screws and the longer screws through the spacers corroded/rusted and broke. Not many but I remember reading a couple of posts.
Rifle will not sell their "tuning block" as a separate item. I wonder if copying their design could be grounds for a lawyer's letter to cease and desist?

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Good point MM2.
I can easily change the bolts if rust starts to invade my SS parts.

cpsfjr said:

I've had the Skyway spacers for about a year now on an '03. They work well and I'm pleased; it's a simple mod and makes a noticeable improvement (not huge, but enough to make a difference for me). I like the looks as well as the functionality. The w/s (a Yamaha touring screen) doesn't stand up so vertical, so it not only looks better but reduces backdraft.

My screws are stainless steel and don't appear to have any rust at this point.

So far, so good. :thumbsup:

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I noticed a huge difference. I was ready to buy a 14" or smaller shield or cut one down for better air flow to my body. With the spacers I get plenty of air to go thru my mesh jacket. Yesterday it was in the mid 70's riding home and almost too cold with the shield down. Johnny80's uses his V-Stream year round now due to his improved air flow, and he lives where it's really hot. :dribble:
Good stuff guys, thanks.

FJRBluesman, that's some really good info. I never even heard of tuning blocks until now.

I wonder if you could get something that goes in between that gap? Perhaps a piece of metal that would be able to fit inbetween that bolts/spacers so that the entire assembly is reinforced?

FJR-Voltron said:

FJRBluesman, that's some really good info. I never even heard of tuning blocks until now.I wonder if you could get something that goes in between that gap? Perhaps a piece of metal that would be able to fit inbetween that bolts/spacers so that the entire assembly is reinforced?

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Not necessary. Just make sure your bolts don't rust out. Keep it simple.

madmike2 said:

Some people did not use stainless screws and the longer screws through the spacers corroded/rusted and broke. Not many but I remember reading a couple of posts.

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I remember people thinking it was the rust too. But to be honest, I just don't see how that is possible in such a relatively short period of time. It is more likely that they were flexing, causing metal fatigue, due to the plastic spacers that were being used.

Rifle will not sell their "tuning block" as a separate item. I wonder if copying their design could be grounds for a lawyer's letter to cease and desist?

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We don't even know if Rifle has patented the tuning blocks. If they are patented, and the ones you wanted to make were identical, then yes they could go after you. All you would need to do is change the design slightly. Also, since Rifle doesn't actually sell the blocks it seems like it would be hard to pursue.

Told ya. Like 4 years ago. Took ya long enough. Kids.......................

One possible problem with broken windshield bolts maybe the joining of dissimilar metals. The two metals just need to be touching each other for possible erosion. There needs to be some sort of coating of insulation between most different types of metals. Stainless steel and carbon steel is one of the worst. The stainless will get eaten up in short order. I didn't find a good explanation but this is the basic idea.

https://trailer-bodybuilders.com/mag/trucks...similar_metals/

If this adds to the dicussion, I had a failure of the bolts last Friday. Very interesting getting the blast after getting out from behind a big van for gap chasing at 80+. Lucky the plastic bolts held the shield in place. I had spacers and fully agree they are a wonderful addition to the shield aerodynamics. Mine is a Gen I 05.

The forensics of the ruptured bolts points to a fatigue failure (repetition of load cycles), no corrosion. My recommendation: Replace bolts at a cycle of two oil changes (6K miles for me).

This is what I will do so as not to increase my laundry bill on soiled underwears.

Klunk,

What type of spacers were you using? The plastic ones from the hardware store? Or something metal?

Enquiring minds, and all that...

Fred W said:

Klunk,
What type of spacers were you using? The plastic ones from the hardware store? Or something metal?

Enquiring minds, and all that...

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Nylon spacers. I know where you are getting to. Bending of the bolts by lack of lateral support.

I examined the bolts with my superman X ray vision and still believe (because of the structural configuration of the windshield support) that the fatigue rupture was induced by push and pull (centered load, not bending). If this is true, the material of the spacers would have no influence on the failure mode.

I still vote for preventive maintenance of the bolts, with a replacement regardless of state at specific cycles. These are inexpensive parts and I started carrying two spares with my spare parts cache.

Yeah, you are absolutely reading my mind. I think your assessment may be a bit flawed.

I'm not a metalurgist, but I slept at a Fireside Inn Saturday night.

Bolts and machine screws have the greatest (tensile) strength in the direction of their length. In fact I doubt you would ever be able to break a bolt in half just by pulling on it lengthwise. You'd probably pull the threads out of the bracket first. OTOH, they have much less strength laterally, especially if unsupported, and reduced much further when bent.

If the windshield bolts happen to let go at an inopportune time it could be catastrophic. At this point in time, I would encourage anyone using plastic spacers on their windshields to replace them with some sort of a solid metal spacer as soon as possible. By tightening the windshield bolts with metal spacers you will be making use of the bolts tensile strength to hold those metal parts together. There will be no flexing and so, less chance of them failing.

The jury is still out as to what material bolts to use. Some say rust is the problem with carbon steel bolts. Some say that you'll get dissimilar metallic corrosion if you use stainless with the steel bracket.

I do know that stainless steel is not the strongest stuff to make a fastener from, and you do run a risk of galling of the threads during tightening, which can reduce the fastener's strength (with SS).

When I do the spacer thing I will be using steel spacers or non-graded nuts, grade 8 flat head screws and blue Loctite. Coating the cap screws with Loctite should keep them from rusting at the threads and a little grease on the threads that stick out should allow you to unscrew them later. I'm thinking I will grind or file the nuts/spacers at an angle on one side so the pressure is even all around.

Thanks for pointing that out to me Fred. I actually went out to my bike to take a look. My bad.