st1100 windscreen mounting tweak?

[Alberto]

I like design and style of st1100. But I think I found some kind of engineering design flaw in the way how windscreen is mounted on the bike. How I understand, it is mounted not directly to a sub-frame, but via plastic. This is the reason, why screen is dangerously oscillating with part of the plastic when riding on bumpy tarmac roads, and bends under pressure of ram air on high speed.

I'm thinking, maybe there is a way to extend somehow subframe to upper point where upper mounting screw is placed. Ill make measurements and decide is it worth or possible to do it, when I take off front plastic, but anyway, I'm wondering, maybe someone have already come up to this idea)

 

[sirepair]

Millions of miles by ST-1100 riders around the world, and I've not heard of anyone modifying the windshield mounts due to worrying about the "flex". Most of the windshields will flex MUCH farther before breaking than is possible to bend while under normal circumstances.

Also, did you consider that building a steel frame inside the cowl to support the windshield would be quite a dangerous item to encounter should you have a collision with something?

 

[Uncle Phil]

It's a bit like the saddlebags and the Hondaline trunk - they were designed to flex some so they do not crack. That's why the windshield screws are screwed into rubber grommets. Some people 'fix' the saddlebags to keep them from flopping, but it's just not an issue. I've got 4 ST1100s and over 400,000+ miles between the four, been on all sorts of roads (if you want rough pavement, try Alaska! ), and the windshields have never been a problem. And I run the 'barndoor' type - Clearview XLs.

 

[John OoSTerhuis]

FYI FWIW

Years ago there was a fellow on the old ST1100 email/listserv (“Hondasaurus”?) that had installed a huge (Goldwing?) windshield and farkled custom support struts from the frame through the Pocket Fairings to the shield. I may even have a low res pic somewhere on my old computer backup CDs. Uncle Phil’s got it right though... not needed.

John

 

[Ron]

In the dark back corners of my memory, it seems someone glued strips of metal inside the plastic the windshield is mounted on. I might be wrong. On one of my 1100s, the grey plastic was cracked and the "horn" the windshield mounted to did flex while on the I'state running 75 MPH.

 

[Uncle Phil]

In the dark back corners of my memory, it seems someone glued strips of metal inside the plastic the windshield is mounted on. I might be wrong. On one of my 1100s, the grey plastic was cracked and the "horn" the windshield mounted to did flex while on the I'state running 75 MPH.

Yes, I think that was the same feller that came up with the 'broken tab' garnish fix - Ray Stevens(?).

 

[Smudgemo]

You should check to be sure the plastic is in good shape before doing anything serious. I fixed some broken plastic in one bike and it made a big difference, but the lack of rigidity you describe sounds normal.

 

[Alberto]

I had Suzuki burgman 650 years ago, but remember that part of frame was lond enough and windshield was mounted right on to it without any flexibility. Even if I have good plastic , without any cracks, metal strips or rods would make the same result as it was on burgman

 

[Uncle Phil]

I had Suzuki burgman 650 years ago, but remember that part of frame was lond enough and windshield was mounted right on to it without any flexibility. Even if I have good plastic , without any cracks, metal strips or rods would make the same result as it was on burgman

But in this case, the 'cure' may be worse than the disease ...

 

[ChriSTian_64]

@Alberto the windshield that you have is not the windshield made by Honda, but a third market.
The one you have is a bit higher and maybe wider than the original Honda.

Honda also has the "cat eye" holes in the windshield, to equalize the air pressure differences.

Don't forget, Honda spent millions to design this bike, including test in wind tunnel, more than they usually do for other bikes, because they wanted to compete with an already excellent touring bike, a BMW model of that period.

All this beeing said, there are certainly little things that we can adjust to our particular situation / condition.

 

[CYYJ]

@Alberto :

As @ChriSTian_64 noted above, you don't have an OEM windscreen, you have an aftermarket windscreen that has some kind of additional very large "wing" mounted up at the top of the windshield.

It also appears to me that your windshield is not attached with the original OEM Honda rubber expanding plugs.

I have a ST 1100 with a larger aftermarket windscreen (but without a "wing" like you have) and I have never had any problems with windscreen vibration or looseness in over 200 km of riding. That includes quite a bit of prolonged riding at absolute maximum speed (over 200 km/h) in Germany and on some Tunisian expressways.

I suggest you first investigate the fasteners that are used to attach the windscreen to the motorcycle. My guess that that is the cause of your problem. Next, I suggest you remove that upper wing and see if that makes a difference. That upper wing has a very long "arm" to exert force on the fasteners, and it is possible that you might be getting some harmonic vibration generated by that wing, especially if you are riding in crosswinds.

Michael

 

[Alberto]

But in this case, the 'cure' may be worse than the disease

I dont know, what can happend?)) If windshield cracks, i'd have to replace it...

the windshield that you have is not the windshield made by Honda, but a third market.

You are right, I have 20' inch windscreen and it was not enough for me to stop air buffeting on the top of my helmet, so I had to add additional flap. I'd better buy 22' tall windscreen, but that time I mistakenly thought that 20' would be ok((

especially if you are riding in crosswinds.

maybe it is the case, i have ajusted it to minimise buffetind effect but now it applies a lot of drag and plastic panel right under the windshield lost it's clips, need to fabricate new ones. I also experienced a lot of unreasant resonanse of the screen while riding on "washingboard" kind of tarmacs.

 

[CYYJ]

I also experienced a lot of unpleasant resonance of the screen while riding on "washingboard" kind of tarmacs.

That sounds like a "what came first, the chicken or the egg" type of problem.

What I mean is that it raises the question of whether the windscreen is resonating due to loose fasteners holding it to the upper fairing assembly, or whether the resonance that you encounter on rough pavement is causing the fasteners to become loose.

I still suggest that you begin your troubleshooting by carefully investigating the fasteners that hold the windscreen in place, and if necessary, replacing them with new OEM fasteners. I do strongly suspect that poor performance of your existing fasteners is the cause of your problems - simply because the oversize windscreen on my 21 year old ST 1100 is rock-solid, even at warp speed, after 200,000+ kilometers.

Michael

 

[Alberto]

Don't want to abandon large windscreen, I like how it feels now if compare to OEM winscreen. Of course I'd like to replace it with 22' Crearview screen just to get rig of this flap.
I'll check fasteners when I get plastic removed, for sure. But I agree that this installation is a bit heavy, thats why I come up to idea to reinforce screen mounting place.

 

[Uncle Phil]

I dont know, what can happend?)) If windshield cracks, i'd have to replace it....

But if the 'mod' ends up cracking the upper fairings (which Honda does not make any more) due to lack of flex, you will have a really hard time finding replacements.

 

[copeina]

FWIW - I have the 22" clearview (with cat-eyes, +2" width also) and it just never did what I wanted it to. Despite all their hype on the website about recurve to kick the wind up, the thing is straight as an arrow and all it did was move the wind from my chin to my eyes. So I've been experimenting this season, and the most comfortable solution I found was mounting one of those wings to the stock windshield. I'm 6'2 and have 1" risers on the bars, and depending on where I set the wing, the wind and rain goes right up and over me now. BTW, that wing is $30 on Wish vs. $150 at the local store and the quality is perfectly acceptable.

At 140km/hr+, the bike definitely begins to handle differently, but 200 is still possible. I was also pleasantly surprised that my mileage is unaffected by it.

However, with the clearview + wing, handling was exponentially worse. The windshield flexed weirdly, and the bike actually begins to oscillate. 150km/hr was about as fast as I ever felt comfortable with that configuration. Without the wing on the clearview, no handling problems at all. I do use the rubber grommets on both shields.

Aerodynamics are a wonderful thing. The ST is a brilliantly designed bike right off the showroom floor. I think most mods only make it worse.

Hope that helps, and you find your best configuration sooner than later.
/K

 

[Alberto]

However, with the clearview + wing, handling was exponentially worse

looks like I'm experiencing similar situation, exept I defeated buffeting on speeds above 150 km/h. Handling is ok, but I see that all construction is under stress on speeds above 170, don't want to exceed the limitation. But I prefer to leave this wing despite I don't like how it looks because without it I have air buffeting right above top of my head, very uncomfortable.

I regret that I have thrown away my old OEM windshield, because it was totally weared off and misty. Maybe, I could test it with that additional wing or use it as a base to make something similar to Madstad that I came across recently on this forum. Considering to buy this setup - it looks strange but not bad...

 

[Uncle Phil]

Some folks use the Laminar windshield with the lip which is usually a bit shorter.
You can see a picture of one on my 'for sale' page.

 

[ChriSTian_64]

FWIW - I have the 22" clearview (with cat-eyes, +2" width also) and it just never did what I wanted it to. Despite all their hype on the website about recurve to kick the wind up, the thing is straight as an arrow and all it did was move the wind from my chin to my eyes.

So I've been experimenting this season, and the most comfortable solution I found was mounting one of those wings to the stock windshield.

However, with the clearview + wing, handling was exponentially worse.

Aerodynamics are a wonderful thing.

Hey, @copeina , thank you very much for that input.

I was thinking about ordering a tall windshield from clearview. They certainly work OK at "normal" speed though. But... yeah, they are tall. And I had some concerns for aerodynamics, resistive force and miles per gallon.

I curently have a National Cycle windshield (from previous owner). 2 inch vertically taller that the original. Yes, it creates some turbulences at freeway speed. And I was thinking at something taller since flyes still like to explode in my helmet visor. I tried it at 169 kmh last fall.

I recently found a second hand OEM windshield and decided to give it a try, despite my 6' 1". I want to keep my ST looking as original as possible (see how I'm silly).
I will now look for one of these shorts "wings" sandwitched over the windshield, and see how it works.

Thanks again.

Very appreciated.

 

[Smudgemo]

I was thinking about ordering a tall windshield from clearview. They certainly work OK at "normal" speed though. But... yeah, they are tall. And I had some concerns for aerodynamics, resistive force and miles per gallon.

I'm 6'1" and don't care for mine much. And that's not even considering what a sail it is for side gusts. I'm currently using a Laminar Lip that I like better, but don't love. I'm thinking of trying a shorty from one of the usual vendors so I get full air (totally okay for California summers) and a Givi Airflow add-on for some adjustability and protection when I want it. The truth of the matter is that the screen that works best for you depends on your personal build, the saddle you're using and your expectations. So to ask anyone for what's best isn't a question that can be answered unless you solicit an opinion from someone your same size using the same saddle doing the same sort of riding, and then, maybe..
Unfortunately it's a crap shoot that's not cheap to solve. Easy to switch screens out, for sure, but where to get the demos..?