Back on July 27th I posted a blog entry that discussed the engine heat on our Harley 110″ motor. I don’t remember if I mentioned I’d removed the vent doors on the lower fairings to increase the amount of air flow around the motor, but it was something that actually worked. The only down side is that the openings in the lower fairings looked a bit odd. I’d thought about seeing if I could fit some type of screen material to the openings that would still allow for increased air flow while making those huge openings a little less obvious. However, the more I considered just how much a screen material would restrict air flow the more I realized it was not the right solution.
While reading some of the more recent posts at the CVO Harley forums someone mentioned they’d cut back their vent doors to increase the airflow and that rekindled my thoughts on what I might be able to do with the vent doors on Blue. Here’s what the other CVO Harley member had done:
My mind went to something a bit more ambitious in that I wanted to remove more material from my vent doors and then cover that opening with a minimally restrictive screening material. However, before doing anything I ordered a new pair of vent doors from Surdyke Harley-Davidson ($11.32 each) so I’d still have the full-coverage doors for the winter and, well, just in case my summer vent door project didn’t yield a useable product.
So, this morning I decided to take on the project and as the first step I traced the opening on the vent doors so I could know how much material I’d need to remove. I used a Dremel tool with a heavy-duty cutting wheel to remove the excess plastic material from the vent door, and then used the Dremel sanding barrels to clean up the corners and edges. I wish I had a table mounted jig saw as that would have made for a cleaner cut, noting I had a couple buggers on the left-hand door. Oh well, not bad for a prototype effort.
With the openings now about as large as I could make them I headed to Home Depot to see what I could find as a screening material. I decided to go with expanded steel mesh as it was about the least restrictive material I could think of for this application, similar to the radiator grill on my Toyota Tundra.
I cut and then contour the mesh to match the vent door profile.I decided to use two sets of stainless steel nuts, bolts and washers to secure the screens to the plastic doors, putting them where there was sufficient “meat” to minimize the likelihood of stress cracking the plastic door material from the bending loads that the aero drag will cause and also left on an extra “row” of the expanded mesh to further distribute any wind loading on the mesh to the plastic body of the vent door. I seated the mesh on the door using a bead of silicone caulk around the perimeter of the opening to provide a little extra holding strength but mostly to act as an insulator against vibration between the mesh and plastic door.
Once the silicone was dry I coated the doors with spray-on “Plasti-dip” paint, a heavy-body latex rubber spray-on paint product. I’d thought about leaving the expanded metal unpainted but that didn’t create the appearance of mass filling the lower fairing vent door openings that I was looking for since the silver mesh blended in with the chrome and granite colors and textures of the motor. Once coated I really liked the look.
So, here they are installed back on the bike. I’m pretty pleased with how they turned out. It’s great having all that air flow and I like having something covering those lower fairing openings. It will be interesting to see how they hold-up over the long-haul.
Actually, seeing how much coverage the solid part of the vent door still provides, I’m not sure that I’d need to switch out the ‘summer vent door’ when temps drop as there’s still more than enough coverage. Yes Harley, I’d like a royalty on this ‘Summer Vent Door’ (Pat. Pending).
This would be an easy design change for H-D or a pretty strait forward aftermarket mod. Ideally, a plastic version of the expanded steel ‘mesh’ would be used to reduce the weight / cost of the ‘Summer Vent’.
September 26th Update:
Decided that the expanded steel mesh is definitely too heavy for this application given that I had to remove one of the three molded-in support arms when I created the opening. There was just an excessive amount of door vibration that I could see at idle which I’m sure is always present. Left as is, I suspect there would be come collateral damage to the lowers from friction and/or stress and that’s unacceptable.
Near term I’m back to no doors since it’s still warm here and have ordered a sheet of aluminum mesh that should be much lighter and still provide a certain degree of mass in the vent door opening. If this mesh isn’t strong enough to hold the needed contour I may try a sheet of ABS expanded mesh.
Regardless, definitely digging the added airflow and like having “something” in those openings.