looking for suggestions for improved aerodynamics on a naked motorcycle

[speedrattle]

well, i can't take credit for foresight, but the 90's GSX750 wheels i'm using have a hole in each spoke perfectly positioned for a threaded rod or even just a through-bolt.



i don't know why suzuki put them there but i know what i'll be using them for.

the pizza pan idea is brilliant. it reminds me of the old british road racers who used to scrounge metal biscuit-tin lids to use for number plates.

[donpearsall]

Suzuki knew that you wanted wheel covers. That why they put the holes there.

Actually I think those may be drain holes for water that may get into the spokes.

Also, consider ordering 4 pizza pans unless you are one of those who can get things perfect on the first try! Now I have spare pizza pans with holes in them.

Don

[Doc B.]

There is also a pizza pan separator. This is a flat round, without the rolled edge. Not going to be as rigid, but makes for a flush cover on a spoke rim. And there happened to be a size that was a perfect fit for an 18" rim (I think 19?). For the center holes I clamped the pan to a sheet of 3/4" ply and used a Dremel mounted on a circle cutting attachment. I drilled the edge of the drum between spoke holes and mounted the brake side cover with 6 screws. The sprocket side cover is attached to that cover with three spacers and screws spaced about halfway out to the rim.

[Koncretekid]

Kevin,
Just remember that with a disc brake, you have to get a disc that is small enough to hug the spokes.  Otherwise, you won't be able to fit the brake caliber over the disc.  Here are the two versions, one on a drum brake, and one on the disc brake wheel. Can't seem to post photos today.
Tom,

[Old Scrambler]

I had my covers made from flat-sheet alloy............water jetted to fit. Then attached weather-stripping to the rim to keep rattles and vibration to a minimum. You could use any rear wheel with a small drum-brake to keep things simple.

[speedrattle]

hmmm

thank you doc and scrambler, the pizza pan separators are certainly less bulk than the pans, and buying 24" x 24" 1/16 5052 aluminum is a possibility.

but tom, your point about the brakes is critical, because the caliper is going to need some re-thinking. i'm using a bog-standard 1970's triumph lockheed caliper on the katana disc that came with the wheel, and it comes within about 1/4-inch of the spokes. hard to see here in the dim warehouse, but arranging clearance for the caliper is going to need a bit more space.



no issues on the sprocket side



looking right down the disc the close quarters on the caliper shows up better.



no interference with the holes in the spokes-- they're abouut two full inches outboard of the caliper.

the only reason ici s went with this caliper is that it's the one i had on the forks when i ran a front brake. a physically smaller caliper on the disc or an offset disc would pull away from the wheel enough to get clearance, i think. or one with less thickness on the disc side. the mount is just a triangular piece of aluminum with three holes in it.

i don't need much of a brake on this. the only time it gets used is unloading and stopping in the pits

[gowing]

question:
would running a full disc on just the drive side and not the caliper side be of any/much benefit?

[salt27]

question:
would running a full disc on just the drive side and not the caliper side be of any/much benefit?

No idea if it does or doesn't but that's what I'm doing because of clearance issues.

  Don

Also, I'm using an aluminum catch pan for a water heater, because I have it.

[bones]

Speedrattle
                 Look for a rear caliper of a late model sports bike. They are usually
                 a single piston  with a floating caliper.  If you can make it work you
                 will save a lot of room on the inside.
                 the disc you have fitted is a front disc. Maybe a smaller rear disc could
                 be adapted to help with clearence.
         
                    cheers   Bones

[Rickr]

  Speedrattle, I have two fenders that might work for you. They were made for a narrow glide Harley front end with a 19 inch wheel.  I can't post pictures so if you're interested give me a call. 904-6 two two-six 38 one Thanks, rickr

[speedrattle]

bones, i spent some time on ebay last night looking at smaller calipers, and spent fourteen bucks on this (free shipping!) to do some experimenting





rear caliper from a 2007 kawasaki ninja 250. two piston, but floating, as you suggest. looks a lot smaller on the inside than the lockheed fixed caliper i have now.

i]m using the huge front suzuki rotor because that's a front wheel on the back, and i knew it would fit. i don't have a junk yard anywhere near me to go measure things, sadly, so i end up guessing from pictures.

rick, thank you. i'll give you a call.

[Koncretekid]

I'll try again.

[Koncretekid]

Here's one of the wheel before fitting the wheel disc.  The disc is mounted directly against the inner rim  and gives just enough clearance to fit the caliper.

[speedrattle]

i see what you're saying. internal clearance is the issue. i just went down to the shop and measured, and my fixed lockheed caliper is two full inches thick between the outboard surface of the rotor and the inboard bolt head mounting the caliper. dual acting pistons, so that distance is fixed.

my daughters race a 2007 250 ninja, which is why i thought of that little caliper. i measured the one on their bike, and its only 1.1 inches for the same distance. new pads, so that will be the maximum extension inboard. i think that will give me the clearance there i need. also, there are two lips on the katana rim, one along the outer bead, and another just outboard of the spokes. i think i can set a pizza separator tray right against the spokes on that inner rim and still clear the caliper.