Drilling the windscreen

[Kevin2109]

I cant find ANY info on this! but Ive seen it a lot on the Isle of man TT bikes and some other race or touring bikes. They seem to drill 3-6 holes in the bottom on the windscreen, I'm guessing this is to relieve a little bit of wind pressure when it goes over the top? Maybe it keeps the wind down behind because of the pressure release

Any Ideas? I'm about to just drill into mine and see if it changes anything

[alex.s]

wear a condom.

[dubojr1]

Originally Posted by alex.s

wear a condom.

[Kevin2109]

Originally Posted by alex.s

wear a condom.

God damnit alex!

[headshrink]

I haven't heard of that, but it does sound similar to that "air curtain" design the last 650r had.

[cuong-nutz]

Originally Posted by Kevin2109

I cant find ANY info on this! but Ive seen it a lot on the Isle of man TT bikes and some other race or touring bikes. They seem to drill 3-6 holes in the bottom on the windscreen, I'm guessing this is to relieve a little bit of wind pressure when it goes over the top? Maybe it keeps the wind down behind because of the pressure release

Any Ideas? I'm about to just drill into mine and see if it changes anything

I think you may recall a thread about a british company making windscreens for the 250 where there's a hole at the bottom of the windscreen. It's to reduce the buffeting/vacuum effect when you're tucked behind the windscreen........or something like it.

[Kevin2109]

So tempted to drill -___-

[cuong-nutz]

http://www.ninjette.org/forums/showt...9&postcount=12

post 12 my sneak78
http://www.redracingparts.com/englis...RNinja2005.php

[headshrink]

I'm interested to see what a drilled screen looks like. It seems like a pretty small gain (over DB) if it looks bad.

[CynicalC]

Speed holes, eh?

[saxnbass]

Is it the same concept as some of the super sports having the windscreen not attach at the bottom and having a gap? (Like the current ZX6r)

[Kevin2109]

Originally Posted by saxnbass

Is it the same concept as some of the super sports having the windscreen not attach at the bottom and having a gap? (Like the current ZX6r)

This is what im thinking too, Yamaha has been doing it for a while on the fzr... Hmm I'm going to go drill

[saxnbass]

Report back with pics and if it feels any different riding it.

[Kevin2109]

Step 1:

Drill 3 small pilot holes half an inch apart

Step 2:

Drill 3 holes with a 11/64th bit



Step 3:

Angle the drill bit down as its spinning to open the hole in the direction of the air

End result:

[Kevin2109]

I'll let you guys know if it works or not

[outasight20]

Those holes seem too small to have much of an effect. I'm curious to hear if it makes any difference.

[Kevin2109]

Originally Posted by outasight20

Those holes seem too small to have much of an effect. I'm curious to hear if it makes any difference.

We will see what happens, I didnt want to drill big ass holes and have it not work lol

[alex.s]

its crooked.

[Kevin2109]

Originally Posted by alex.s

its crooked.

I hate you

[alex.s]

<3

[headshrink]

Actually I don't think that looks bad at all. I'm also guessing they are too small to have much effect, but you may be on to something. This is where nicely sharpened drill bits will come into play.

[Kevin2109]

Originally Posted by headshrink

Actually I don't think that looks bad at all. I'm also guessing they are too small to have much effect, but you may be on to something. This is where nicely sharpened drill bits will come into play.

Actually, be very careful with sharp bits and acrylic, its much better to drill with a dull bit. The sharp edges will catch and will shatter the plastic thats why its better to use different sizes to get to your final goal

[headshrink]

Originally Posted by Kevin2109

Actually, be very careful with sharp bits and acrylic, its much better to drill with a dull bit. The sharp edges will catch and will shatter the plastic thats why its better to use different sizes to get to your final goal

Good to know, thanks for the clarification.

I'm thinking a deremel tool might be a good alternative to a regular drill. Do you agree?

[Kevin2109]

Originally Posted by headshrink

Good to know, thanks for the clarification.

I'm thinking a deremel tool might be a good alternative to a regular drill. Do you agree?

unless you have water pouring on it the whole time no, ive used them before and with it spinning so fast the bit heats up and melts the plastic/acrylic If its a variable speed one then you should be fine but a normally drill has been the easiest to work with so far

[leed]

The vents diminish the low pressure zone between the rider and the bike, and thus reduces the turbulence in that area (most notable when your head/helmet shakes back and forth). Those holes are too small though :P

Some examples:
S1000RR (comes stock, but this shows the holes easiest)


An aftermarket for the Ninja 650R


Ninja 1000 (More of a raised windscreen)


If I had to guess.. A lot of pro circuit bikes don't have this as they tend to move in and out of bike more than road racers do, so the turbulence is not as discomforting/irritating. Iono though. The whole vented windscreen looks to be very popular among sport touring bikes for obvious reasons!

And you can probably get away with a grinding wheel in a drill and a vacuum to suck up the chips/dust. Patience, patience, patience! Also: The stock 250 windscreen is polycarb and not acrylic, so you have to be even more careful with drill bits that can catch!

[choneofakind]

Originally Posted by Kevin2109

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looks good! Interesting theory on the pressure differences, but I still won't be drilling my windscreen anytime soon. Spent too much on that dang ZG double bubble to eff it up

[choneofakind]

http://motorcycleinfo.calsci.com/Fairing.html

Nearly all of our windshields have vents. These vents are part of the aerodynamic design of the shield, to reduce turbulence and noise. They are not there to make a flow of air on the rider. When you're riding on the highway, any windshield is pushing air away from the rider. This leaves a low- pressure pocket between the windshield and the rider. The air flowing past the motorcycle wants to drop into this low pressure area. If the outside air is allowed to spill into the area between the windshield and the rider, the result is turbulence, noise, and drafts. When outside air spills into the rider area, it almost always falls in a curved path, causing spinning vortices of air. These vortices are noisy and can cause the battering and hammering on your helmet reported by some riders. Our windshields and vents are designed to funnel air into the rider region to relieve this low pressure area and greatly reduce the tendency of outside air to spill in. The vents are designed so that the air coming through them is quickly dispersed, leaving almost no detectable air flow at the rider. Our goal is to produce almost completely still air on the rider with no back pressure.

[headshrink]

OK - dumb question.... on a REALLY cold night, in a tucked position, would it be any colder behind a vented shield vs. un-vented shield?

[choneofakind]

I doubt that those 3 little holes are going to make any significant difference in temp, considering that the engine is releasing heat right there.

[CZroe]

Originally Posted by choneofakind

http://motorcycleinfo.calsci.com/Fairing.html

Yup. Our 250s have vents too, it's just routed through the upper fairing before being vented under the windscreen. I've has all kinds of stuff bubbling up from that vent at speed in the rain!

[cuong-nutz]

Originally Posted by CZroe

Yup. Our 250s have vents too, it's just routed through the upper fairing before being vented under the windscreen. I've has all kinds of stuff bubbling up from that vent at speed in the rain!

Same here. Seen that happen. Only way for sure is to get an answer from the engineers who designed it or do some good ol testing.

[leed]

Originally Posted by headshrink

OK - dumb question.... on a REALLY cold night, in a tucked position, would it be any colder behind a vented shield vs. un-vented shield?

In theory, no, it shouldn't be any different.

Originally Posted by CZroe

Yup. Our 250s have vents too, it's just routed through the upper fairing before being vented under the windscreen. I've has all kinds of stuff bubbling up from that vent at speed in the rain!

I've never had anything come up there. In fact, that area is a complete dead zone of no flow whatsoever! On the New-Gen 250's the only place I could see the vent being is at the very front of the windscreen where the dash, so to speak, doesn't go to the very back. But there is nowhere for flow to come from. Everything from there to the front is sealed, except for the nooks and crannies between pieces. You can put an envelope there and ride for days without it moving unless you hit a bump. But perhaps it disperses so quickly it can't be noticed. But if I shove it full (say with plastic bag or something), I've never noticed more buffeting than when it is open.

@choneofakind 's quote was from a website that manufactures aftermarket windscreens (See the Ninja 650 windscreen photo above).

[Kevin2109]

So today I finally had a good little ride to see how the holes are, it could be a plasibo but I feel that they make a pretty good difference! Its not huge but in a tuck it is for sure nicer, and it was windy as **** today and it felt better. Even at a 125 it felt a lot better (not like I would know )