169 replies to this topic

[MCBodge]

The 'dual layer' screen is now fitted, but there's a gale blowing outside so I'm not taking it for a test

[slocoach]

I notice that the latest MRA Vario screens for the Honda 1000CBF AND THE 1000 Varadero each has 2 triangular holes approx a third to a half way up from the bottom. Does anyone know whether the latest ones for the TDM Mk2 has these?

Ps. Was out for a run today and met a Varadero Rider who on seeing my TDM told me that he had been camping in the Dordogne this summer and there was a group of around 10 all with TDms on the same site. Small world isn't it!

[MCBodge]

I took the newly-screened TDM a short way down the motorway this morning on the commute.
Test conditions weren't ideal as there was a fair bit of traffic and a bit of a cross wind.

The height of the standard screen (raised slightly to clear the top of the cut-down screen) did reduce the pressure on the shoulders and throat which was more comfortable than with the cut-down screen only.

There didn't seem to be much helmet noise/tubulence, but I only briefly got up to speed so this will require a longer ride to determine if it is an improvement and not just a placebo effect.

As we had the first frost of the season over-night, I was also wearing my winter neck warmer and Buff which seals the gap between my chin and helmet -possibly reducing noise a little.

There didn't feel to be much air coming up between the screens so a larger gap at the bottom may be worth trying.

If I do decide that using 2 screens helps I'll buy a set of stainless fasteners and make some more permanent spacers.

EDIT: More testing has now taken place. At low speed my head is out of the noisy zone
-leaning down makes it noisier and up slightly makes it a little quieter.
At higher speeds there is some screen flutter and it is pushed back a bit. I'm going to fit spacers where the screen would ordinarily be pressed against the fairing.

Edited by MCBodge, 05 October 2009 - 05:41 pm.

[Bobajob]

Hi MCBodge and others,

After reading all your exploits I decided to take action.
As much as I love riding my new bike I couldn't put up with the buffeting and helmet vibrations I was experiencing. So armed with a jig-saw I did what you see below. I'm 6'3" and the difference is great, no significant buffeting, no more vibrations and blurred vision, able to hear the engine at 70mph and I don't avoid the motorway any more.

I am considering opening up the slat at the base of the screen to around 70mm wide by 25mm high. Opinions??

My only problem now is the wind hitting my shoulders and making my neck cold but a buff should sort that out.

Bob

Attached Files

•  Screen_fitted2.jpg   69.51KB   65 downloads
•  Screen_cutdown2.jpg   82.57KB   45 downloads

[MCBodge]

...the difference is great, no significant buffeting, no more vibrations and blurred vision, able to hear the engine at 70mph and I don't avoid the motorway any more.

Good news.

My only problem now is the wind hitting my shoulders and making my neck cold but a buff should sort that out.

You're taller than I am and have cut your screen further than I did so there must be quite a bit of pressure on your shoulders. I'm trying to reduce the buffeting but keep the screen height.

[Bobajob]

You're taller than I am and have cut your screen further than I did so there must be quite a bit of pressure on your shoulders. I'm trying to reduce the buffeting but keep the screen height.

Correct, but the increase in pressure on my shoulders is more than compensated by the reduction around my head. I looked at all the comments and figured I was going to have to cut the screen down considerably or go for a huge screen to push the air over my big head. I took the cheap and cheerful option as I sourced a cheap spare screen on Fleabay.
I don't know that my choice of helmet (Caberg Trip) helps or not but it's all I could afford at the time.

I've got a spare screen so may try some more mods in future.
Keep up the good work.

[MCBodge]

I made the observation that you had to be either "in" or "out" of the airflow as in a big or small screen but not inbetween. I reckon that was a valid comment borne out by other contributions.

I agree, but I'm trying.

I did appear to be getting a smooth airstream towards the top of my helmet with my sandwich screen yesterday, which was good. There was turbulence lower down which produced noise if I ducked down.

At speed there was insufficient rigidity so I've now packed the sides of the screen to stiffen it and raised the leading edge further to let more air through. If it doesn't help then I can always just take the top screen off, trim the shortened further and get used to the breeze.

Edited by MCBodge, 07 October 2009 - 08:43 am.

[MCBodge]

Initial findings with latest mods:

At an indicated 60mph it felt fairly effortless. My jacket was flapping a bit, but the head/helmet felt comfortable.
At 70mph it felt similar and no pressure on the shoulders.

At an indicated 80mph (for only a short time) my head felt more comfortable than usual and there was no obvious screen fluttering.

The main stream of air directed by the screen(s) seems to be less turbulent than it has been before and the screen copes at motorway speeds.

It looks as if there are similar solutions available for the Goldwing:

Edited by MCBodge, 07 October 2009 - 01:14 pm.

[gabby]

Been reading this long post for some time and have finally got around to experimenting and making a version of a dual layer screen that works for me so will share my findings. I didn't want to cut down the standard screen because I like having my neck out of the wind on this bike. I didn't however want anything too high that would flap around and that I would have to look through.
I found the standard screen produced an almost knife-edge sharp line across the bottom of my visor where the wind hit it if I held my hand up; a very distinct change in a small distance that was very noisy. The modified screen leaves the bottom of my visor in the clear and I have a more gradual change in things over a greater distance. The very distinct change has gone and it's quieter. It's basically diffused the air stream coming off the screen.

I moulded some acrylic into the shape of the standard screen but made it more vertical than the existing top half. It extends vertically about 50mm higher than the existing. It is spaced off by 6mm bar using longer screws. This results in the bottom of the added screen being clear by about 6mm at the bottom and 30mm at the top. The holes are an addition today which seem to diffuse the air stream even more so another row higher is the next thing to try.
Anyway, the photos will show it better than I can explain. See here... if I can get links to work:
http://i735.photobuc...00/PICT0075.jpg
http://i735.photobuc...00/PICT0076.jpg
http://i735.photobuc...00/PICT0078.jpg
It's still only a prototype really and looks a bit agricultural, but is a definite improvement and seems indicate people are on the right track with holes and a dual layer. Or both in this case.

[Geordie Guy]

Now that looks FANTASTIC !!!!!!

I like the way you have mirror'd the curve, it looks brilliant.

What is the reasoning for the two metal bars ?

And how the hell have you made it, looks a bloody professional job to me.

Great stuff , Gabby.

Edited by Geordie Guy, 11 October 2009 - 09:02 am.

[Studley Ramrod]

Spot on ! Looks Great ! Here ya go Gabby !

[gabby]

Thanks guys. The two aluminium retaining bars with dense foam under are just to avoid small stress points at each screw head and keep it strong. It is rock-steady, although I've had it up to only 130km/h or so. 3mm acrylic sheet is very cheap and surprisingly easy to work with and this was my first effort at it. If it's heated to 150C or so for 10 mins it is as flexible as rubber sheet until it cools.
I took off the existing screen and covered it with cloth and used this as a mould to get the shape right. I heated the sheet until it was flexible then held it in place on the mould. Note that I am NOT suggesting heating it in a kitchen oven so you would need to do your own research on that because it can give off fumes that will ignite if significantly overheated for too long
There was a lot of fiddly work in doing this first effort of course. The point was to see if a dual layer, half-screen with a steeper angle and an increasing spacing worked. Seemed to for me. Just food for thought and some more research perhaps.

[MCBodge]

That's superb work.

From further riding, my sandwich screen is great up to about 70mph. As speed increases further (in my private wind-tunnel) the stream over the top presumably dominates the secondary stream under the screen and there is more turbulence.

I've now spaced the upper screen even further away from the lower screen. I'm going to pack it more firmly to stiffen the system up.

[TimH]

Yeah, great work Gabby, excellent job with matching the curves top and bottom to the original screen, looks very professional – you should go into production!


Did you consider using polycarbonate instead of acrylic? If so, why acrylic? Is it easier to work with?? I just ask because I stumbled across this video on Utube which seems to suggest polycarbonate might be better if your screen is getting shot at, or a road raging cager is laying into your bike with a baseball bat.... Does anyone know what the standard screen is made out of?

While searching the net for polycarbonate info I also came across this document which looked useful, thought I'd share it: http://www.theplasti...ssing_guide.pdf.

Moderator – I’m new here so forgive me if I’m out of line, but what are the criteria for pinning this thread? As a new TDM rider, the noisy screen seems to me to be it’s biggest (only?) fault, and this thread already has a number of solutions…..

[gabby]

Cypher, as far as I can work out, acrylics (in their various names) are less impact resistant, but are more scratch resistant than polycarbonates, as well as costing less. There are different grades of acrylic and what I used was a high-impact grade that does not seem to shatter easily under test. In discussion with the plastics manufacturer, I was told that bike screens often use some sort of acrylic like this, as do many automotive products. I've read that Lexan is as easy to work with and form but the plastics supplier told me not to bother. So, no idea on polycarbonates really. If I hit a big red 'roo and it shatters, I'll have bigger worries than the screen chemistry I reckon.

[Studley Ramrod]

If you can source a plastics supplier/fabricator they will often be able to add simple bends to the piece of plastic your going to buy, at little or no extra cost !

All about plastics here http://www.theplasti...co.uk/x614.html

Here's my local plastic shop http://www.theplasti...co.uk/index.htm

Edited by Studley Ramrod, 12 October 2009 - 10:24 am.

[TimH]

Some interesting pics found here http://people.bath.a...ycles/aero.html ...

ZX12

notice how the airstream is hitting the rider just under the chin

K1100

and again... notice how the wind deflector on the top of the screen seems to direct the airflow right onto the helmet. Wonder if it would be better without it?

VFR750

I'd guess this one is noisy...

ST1100

not sure what this shows?


Has anyone ridden any of these model bikes? I'd be interested to know how quiet/noisy they are...

and here is a link to this guys research at the University of Southampton - http://www.isvr.co.u...ork/m_cycle.htm - very interesting reading. The links to the pdf files near the bottom of the page were worth a read.

Edited by cypher, 12 October 2009 - 10:17 pm.

[TDMj]

Very nice job.
Did you think about ajustable screen possibility. When i look at photos two metal bars looks like track line to adjust screen up - down.

I think your way may be good solution for made it adjustable.

Good luck !