Inner Cowl Ventilation

[hippo888]

This is what happens when I get cabin-fever here in Michigan. This is my attempt to reduce the horrific heat problem on my ST13. I ordered two new inner cowl pieces and have started to ventilate them with the aim of letting in more air behind the fairing while retaining as much structural integrity as possible.

I should have probably taken off the original inner cowls to see what was behind them so I could logically lay out the ventilation holes, but it was barely above freezing in the garage, so I just put holes everywhere.

I made sure to leave the compound-curved areas of the inner cowl without too many large holes so that it would retain its strength. I'm pretty satisfied with how the drilling turned out.

Now I just have to wait until April to see if it works. Grrr... :mad:

[Mellow]

That looks great! I wonder how many drills are being turned on at the moment...

Hey, I wonder if you're gonna whistle now as your bike cuts through the wind... lol

[crazykz]

That looks like it took some patience. I will be curious to know the results. How much did you pay for the pieces just out of curiosity?

Curt

[hippo888]

Mellow,
Whistling -- OMG! :eek:


Curt,
I ordered the inner cowls from Honda Direct Line. They were about $11-$12 each, but I had to pay shipping since the order was under $100. So I think the total cost was about $13-$15 for each inner cowl piece.

Patience at this point isn't a big problem. I basically either work or ride and it's too cold/snowy to ride so all the drilling was therapeutic. I laid out 1/4" holes with 1/4" spacing between each hole using AutoCad. I plotted out all the holes and then taped the hole-template onto the inner cowl and center-punched through the template. I ended up using a 15/64" drillbit instead of 1/4" because I decided I would ream the holes to clean them up after drilling and that would cause the holes to get larger. In retrospect, the reaming wasn't necessary and I will drill the right-side inner cowl at 1/4"

If anyone needs the AutoCad template, I can email you the .dwg file or plot out a template and mail it to you.

[Kennedy]

I would have to say youve been busy. Should go out and put my mirror deflectors on if I wasn't to damned lazy today.

[dannyk]

Yep! I heard them things act just like deer whistles only at a lower frequency so humans can hear them coming ;) ;) ;)








Only kidding

[beastie]

Wow! Those are beautiful. It puts my cowls to shame. All I did was cut a hole. But then all I have are hand tools. You could market yours.

[tccox]

Hippo

I see you also have a 04. Just wondering , have you spent any time on another ST to see if problem varies between bikes ??

[hippo888]

tccox,

I haven't had a chance to ride anyone else's ST13. Bill has an '04 and lives about 30 minutes away. Next season I'll see if he wants to swap bikes for a bit.

Japanese bikes usually have very tight tolerances. Any bike in a production run is usually very close to any other bike in the production run. This is unlike HDs or BMWs. For example, there are huge differences between Sportsters. Some vibrate very little while others are paint shakers. BMWs seem to vary too. Not as much as HDs, but it's noticeable on a shake-down ride.

I'm betting that the heat issue is mostly one of rider tolerance. I see more complaints from people who live in colder climates and less complaints from people who live in the southern USA. I guess the southern people are used to the heat.

Of course, I don't think anyone has swapped bikes long enough to prove any theory about the heat.

[ssls6]

I've often thought about doing the venting but I worry about rode grime and water collecting around all the electrical connectors behinds those panels and around the tank. I'm still smoking on some sort of seperator that allows air through but allows the water to fall out.

[jsl]

Paul could be right about the cowls, without them the fan will pull air around instead of through the radiator, there could be a problem if you get stuck in stop and go traffic on a hot day.
I just remove them and stay out of traffic. Two hot Texas summers on the ST so far without the cowls and I have never seen the temp guage over three bars ;to me the they are like a heater, I only use them in cool weather.

[tccox]

tccox,

in colder climates and less complaints from people who live in the southern USA. I guess the southern people are used to the heat.

Of course, I don't think anyone has swapped bikes long enough to prove any theory about the heat.


Nope , lived here all my life and you NEVER get used to the gawd awful summers we have here. No , dont think its because Im just used to the heat, in fact would seem folks in the hot climates would complaine about it more. On my two Roadsters sitting in CLT traffic on a 90+ day I'd just about pass out. The ST is not as bad. Anyway, if you ever make it to the BRP would be glad to meet you there and swap for a few miles.

[hippo888]

I'm not too worried about the engine overheating because:

1) The fans are mounted directly to the back of the radiator (I think), so if the fans turn on, they'll draw air through the radiator fins.

2) The steering stem/fork opening through the front fairing is already a huge hole that allows air to bypass the radiator. It seems from other peoples' experiences that adding more holes around the radiator doesn't compromise the cooling.


Like ssls6, I'm worried about debris and the electrical connectors (Honda did not use a lot of water-resistant connectors under the forward fairing). However, I'm hoping the size of the holes keeps out the big rocks. As for the road-dust / rain-carried-dirt, I don't think there is much that can be done. Big bikes like the Goldwing and K1200LT get filthy under their fairings and nothing seems to go wrong. Honda puts plastic booties around the big bunches of connectors. Unfortunately, it seems one of the booties on the right side is open towards the (soon to be) ventilated inner cowl piece. On my '04, Honda stuffed a lot of the connectors full of dielectric grease. That should hopefully keep the grit out of the connectors (although the outside of the connectors are going to turn into little fuzzy, black mounds of dirt with all that grease smeared everywhere).

tccox,
It's weird, but I always felt that the oilhead BMWs were really cool bikes. Much cooler than any water cooled motorcycle. I've had oilheads with and without fairings and I never had the heat issue that I have with the ST13. The old BMW K-LTs are another story though -- they're probably as hot or hotter than the ST13. I dumped my K1100LT after just one season because of the heat coming out of that sucker. If I get the chance to ride the BRP again, I'll give you a shout. Thanks for the offer!

[BentAero]

Paul,

This cowl/drilled cowl/no cowl issue has been hashed & rehashed many times over on the msn board.

I pulled my inner cowls out last spring, (roughly 7,000 miles ago) threw them in the attic, and never looked at 'em again.

My experience has been:
1. It was like adding an air conditioner to the ST.
2. When caught in stop & go traffic on a hot day the fans will kick on a little more often than when the cowls are in. Big deal.
3. No noticeable difference in dirt/debris, etc. behind the area the cowls would protect.
4. Letting the heat out from the 'engine bay' was the best thing I've ever done to the bike.
5. Doesn't make any difference in the function of the bodywork.
6. The cooling system is so big, so good, it doesn't make any difference if the cowls aren't installed. Always 3 bars.


As always, YMMV.

[Fireball18]

Here's what I did. Where Hippo drilled holes in his inner panels, I took a jigsaw and simply cut out the center piece, just about where he has the outermost line of holes drilled. It left enough of the perimeter so that I could snap it back in place with the plastic rivets.

Now---I did that on my wife's bike. My bike's inner panels are still intact. What I noticed was that at 85 degrees out, her bike was noticeably cooler to ride than mine. As soon as I get over this crud I've come down with, I fully intend to do the same surgery on mine. Never had a problem with her bike overheating in traffic, either.

[Pete McCrary]

I want to make sure of what is referred to as the inner cowl:

The inner cowls are the black plastic pieces that fit around the glove boxes that are visible from the seat and not the painted pieces that fit down lower just behind the headlights - correct?

[John Anthony]

hippo - you are one patient dude. I'll be interested in hearing more about your experiences after you got some miles and a summer under your belt. John

[Pete McCrary]

Thanks a million!

[skydog]

If anyone needs the AutoCad template, I can email you the .dwg file or plot out a template and mail it to you.

Hippo,
I'll take a copy of your template if you don't mind. Thanks
skydog@sbcglobal.net

[sandman]

Me Too!

sandman_g@bellsouth.net

Gordon

[hippo888]

Well, I just got back from about 1,000 miles on the ST13 with the drilled fairing panels.

Observations:

It never got really warm in Florida on my vacation. On the one warm day, above 70F degrees, the ventilated inner cowls seemed help a bit. Instead of roasting, nearly unbearable heat, it was just normal, I'm on a motorcycle heat.

I didn't do any testing (not enough time), but I don't think the upper holes do anything -- they are the holes that are located in the steering stem well. The direction of airflow is parallel to the holes, so I think that they only let the fairing glove boxes cool off when the bike is stationary.

Given the strength of the panels, I'm going to drill all the areas where I left strengthening ribs (areas with compound curves). These areas are generally perpendicular to incoming airflow and should allow in more air.

The painted fairing panels are really weak and flimsy without the inner cowls in place. I think you definitely need the inner cowls. There are a couple of tabs that look like they'd break without the support of the inner cowls -- if you search, I think some people have reported this happening when running without the inner cowls.

I still have two panels left, I may drill these, with more holes lower down in the panels (closer to the edges and through the compound curved areas) and not drill the areas up top near the glove boxes.

The most exposed electrical harness connector bunch is behind the left inner cowl. If I re-do the drilling, I will not drill holes directly in front of this connector. I will post pics as soon as possible (it may be a while).

Darn - I tried attaching the .dwg file, but it won't work. I'll just email to anyone who asks. You'll need AutoCad or an AutoCad reader to open the file -- I think there are shareware programs that will do this. The template is simply a bunch of 1/4" holes with 1/4" spacing on a 36"x42" piece of paper. You'll have to orient the holes to your liking and then center punch the hole locations onto the inner cowl piece.

[Fireball18]

Hippo's right, the outer painted fairing panels are not real skookum. The upper tip of the fairing panel and the piece of plastic under the headlight sort of snap together to hold them in place. However, each is held fast with a screw that provides strength and keeps them from separating. If the inner fairing pieces are removed entirely, the blast of wind coming in at high speeds will cause the outer fairing panels to flex and come unfastened as there's nothing to keep them there, and the small tabs can break. One solution is to fashion a piece of plastic or aluminum in such a manner as to overlap the two pieces, and with holes drilled, the screws can be screwed in to prevent flapping of the fairing. My solution is as I described in my post above--I simply removed most of the inner part of the inner faring cowl, leaving about a one inch border. Now it fastens using all the plastic rivets, retains its strength, and allows air to come in uninhibited. Does this make any sense?

[rob.uk]

Hi Paul,

You did a great job with your drilling. I have access to a CNC mill in the UK, and would be really grateful for a copy of your CNC template. Do you have this as a G-code file?

Best regards,
Rob

[hippo888]

Rob,

All I have is a 30"x42" architectural E1-sized sheet in AutoCad. It's only a grid of 1/4" holes with 1/4" spacing. I just taped this grid/template to the inner cowl, center punched all the holes and drilled out the holes I liked.

I tried emailing you through the forum, but it won't let me attach the .dwg file. Could you PM me your email?

[hippo888]

More pics.

left cowl: my ventilated left inner cowl. I ended up holing the compound curved surfaces because there is still so much rigidity still left in the panel.

left no cowl: shows the left side without the inner cowl in place. Please note the exposed wire harness. If you want to ventilate your cowl, I'd leave this area undrilled to protect the exposed wire harness from road debris.

left cowl in place: shows how the inner cowl covers the exposed wiring harness.

right no cowl: no exposed wire harness on this side. Note that you can check the underside of your PCV valve with a mirror-on-a-stick from here.

right cowl in place: right cowl in place.

Things I would've done differently: more holes. the panel has so much structural integrity I should have put holes to nearly the edge of the panels.

last thing: if you've sent me a PM or email asking for the holes template and haven't recieved one, please let me know -- I've been travelling and some correspondence may have been misplaced.

[hippo888]

I've finally put some miles on the bike with the ventilated inner cowls in place. It's been between 90-100 degress with humidity in the high 80% range.

The ventilation works at higher speeds. There is a ram-air effect through the ventilation holes that cools the air behind the fairings enough to keep the blast furnace exiting the fairing under control.

I didn't like the how the holes exposed the electrical connections in the upper area of the fairing so I got another set of inner cowls and instead of a pattern of holes, I just cut out two large triangles in the lower portion of the inner cowls.

Since 1/2 the holes in the "swiss-cheese" ventilation pattern are over the inner fairing pockets, I don't think they help much in cooling. So, the large triangle in the lower portion of the inner cowl probably has as much effective area as do the "swiss-cheese" pattern.

Comparing the "swiss-cheese" and the triangle patterns leads me to believe that the "swiss-cheese" is better at keeping the fairing pockets cool (at the expense of less protection for the electrical connectors), whereas the triangle pattern gives the same leg/ankle cooling effect at highway speeds (and offers more protection to the electrical connectors) but the fairing pockets are hotter.

While the ventilation makes the bike comfortable at highway speeds, it does nothing at surface street speeds. I still bake. Then people on the board started talking about wrapping the headers.

Desperate (heat is one of the two things that make me want to sell the ST13), I went and got some 2" wide Thermo-Tec heat wrap. In hindsight, I should have gotten the 1" wide because it would have been easier to wrap around the tight bends of the headers, but the auto parts store only carried the 2" in stock.

Well, I wetted down the wrap and wrapped my headers to the point where they go from 4 into 2. When wet, the wrap is kind of stretchy. When it dries, it shrinks tight against the headers. I used Thermo-tecs steel bands to secure the wrap.

The heat wrap helps with the heat. I still get hot, but it isn't a painful hot anymore. It's just hot, like a motorcycle hot. The ST13 is never going to be as cool as the GL18, but at least it's normal now.

I think I'm going to keep the ST13 now. :D

[NormanPCN]

Have you thought about adding the swiss cheese on the upper flat part of the cowl only which is beside the fairing pockets. No connectors there and that might help cool the pockets.

[CruisingDog]

OK, another possible solution. Add a slotted hole (45 degrees to the road [level]) with the front of the slot pointing up at the front of the bike.

On top of this add an air scoop (you'll probably find these at vacuum cleaner parts stores). Glue it on with the scoop part facing the road in front of the motorcycle.

I've attached a really crappy 30 second dwg of what I mean. Don't get on my case about the shoddy artistic mousemanship!!!!

[Austin city limits]

Ok,,, I HAVE,,, to ask... :rolleyes:

On top of this add an air scoop (you'll probably find these at vacuum cleaner parts stores).

# 1 ~~~ Why would they have Air Scoops at a Vacuum cleaner parts store???

# 2 ~~~ How did YOU,,, discover they have air scoops at a Vacuum cleaner parts store??? :D

[nisbeam]

It has to be done, my side-pockets are roasting ! :rolleyes: I would like to drill the pattern of holes. Does anyone have a copy of the template in Word format - I dont have Autocad. Thanks. :03biker:

[Austin city limits]

Granted,,, The Template hole pattern looks better than mine,,, but I just got it up on the Drill Press,,, and started drilling... :rolleyes:

Yes,,, Yes I DID,,, drill in straight lines... I did drill my holes a size or 2 larger than was talked about... Instead of having all the holes in nice lined up rows,,, I drilled closer together,,, and the next row in between the previous row... Am I going to win an award from my attempt from "Drill Press News"??? No,,, No I am not... ;) Here,,, is my Farmer Designed,,, Hole pattern ...

O O O O O O O O O O O O O O O O
+O O O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O O
+O O O O O O O O O O O O O O O O

And,,, the answer is no,,, I did NOT,,, cut + into my pieces... I put the + in so to make the rows of O's match up to what the look I had... :p:

What I am saying is,,, No one,,, is going to notice as long as you at least ATTEMPT,,, to keep the rows aligned...

[Erik]

I just removed the cowls..I tried drilling but maybe I didn't put in enough holes or whatever. I ordered new cowls which I'll pop in in the winter I cut a piece out from both sides that is where the screw and one trim rivet go.. holds the panels fine. I was out yesterday but it wasn't hot enough to tell. but it does seem to be cooler without the cowls. It's gonna get in the mid 90's over the next couple of days so we shall see.

[snowmoer]

Here is a photo of what I did. I used a Dremel tool with the dry wall bit. I cut out 1/2" slots and left 1/4" between them. My goal was to cool down the fairing pockets and it did that. It also helped with the heat. I live north of Palm Springs CA, where it is 100-115 during the summer and now I can use the fairing pockets. There is still heat when I ride, but it is better that before the mod.

[hippo888]

Further update.

It's been in the mid 90's here for several days now. Unlike earlier testing, I've been doing some longer rides than my normal commuting. After three or four hours, the heat is just too much. Once the frame and gas tank heat sink, my ST1300 is just too hot, even with all my mods.

I just traded the bike in on a GSXR1000.

I want to thank all of the members of this board. I've learned a lot and had a great time. This is one of the few boards where everyone has been a gentleman. There is a respectful understanding between the members here that is quite rare for these kinds of forums. Maybe the bike "pre-selects" for our kind of people. :)

Wish me luck on the track. Stay safe out there.

[sherob]

I guess it's what you can stand or a YMMV issue. We hit the 100's down here later this month thru August. It's been 94-98 lately with 60-98% humidity, heat index of 100-103. She's been a little warm, but really no warmer than usual. Sorry to see you sell... hope the Gixxer keeps you happy ;)

[Trashman]

Summer arrived early in Texas today 101 for the high. So here goes the inner cowl issue again. My guestion is do you believe that opening up the cowls allow for heat to escape or the increase airflow pushes the heat out the sides of the bike?

[NormanPCN]

It will put ambient temp air inside the mid/upper portions of the fairing. This will help cool some things down. Like the fairing pockets, tank and such.

[Red Duke Rider]

I took my inner cowls off and tossed them in the basement. Made a bigger difference than anything else I did. Bike is noticeably cooler. Can actually be ridden in the hot summer months now.

[Dave Tracy]

Which pieces are you talking about?

[st1300r]

Sitting on the bike look down left and right of the fork tubes. The 2 black flat plastic pieces that box out this area. Sort of running from the fairing pockets down.

[Red Duke Rider]

Carl:

I think the theory that Honda used in putting those panels in there was to force every bit of air through the radiator.

I have not seen any rise in operating temp of the bike and it is actually comfortable to ride except on the hottest of days. I still intend to install a neoprene blanket when I have the tank off for the Turbo City FPR installation.

The only thing you have to do is undo the 4 plastic rivets and use a tie wrap to fasten the ambient temp gauge pick up to.

Whole thing takes about 5 minutes.

RDR

[TahoeBound]

Or just buy an '08 FJR (or 07 or 06)...at least Yamaha has addressed this heat issue BS. And before flamed, know I've owned more Hondas than any other brand. Usually a good product, just don't see them backing the ST. And as much as the ST fits my current "profile" just don't see buying it. For $15 K (ABS) there should not be a heat issue where people say the thing is "unrideable" in the summer. Drilling friggin' inner fairings & wrapping the exhaust - that's just plain BS. FIX IT HONDA! Side note: nor will I buy the new Connie for the same reason - many "heat" issues boiling to the surface (pun intended!).