Much of the following is estimation, mostly because real numbers couldn't be found. If you have better sources for data, I'd like to hear it. Or, if you have any corrections to my estimations or processes, feel free to speak up. (Particularly if it has significant impact for the conclusions!)
Research:
American Honda sold 400,000 units in a 10 year-run. (
http://www.classicbikes.com/750.html)
All CB750 @ 40,000/yr. In 75-78 were the F models (only 3 years).
Let’s say half sold in those 3 years were F models. 20,000 x 3 = 60 thousand.
Further estimate 1/3 of those have survived these last 30 years so that leaves 20,000 CB750F models left in the US.
How many of these need side covers? 20% W.A.G?
That's about 4000 total bikes that need side covers.
I'm going to be generous and say 1/3 of these owners will actually buy side covers if their price is met. That's 1200 covers.
Anyway, it looks like a lifetime stock of 1000 side covers would cover sales needs for the foreseeable future.
How many of these people can you reach with a side cover offer? Again very generous (IMHO 40%) That's 480 possible sales. And, easily less than half of that if "their" price isn't met for a business opportunity of 240 covers.
80-90% of people will buy when they are good and ready, ("Like maybe in a year or two when I get all the other stuff on the bike like I want it.") People also wait for others to review quality and value before purchase. So, there could be some deferred sales opportunity.
Anyway that's 24 covers initially sold fairly quickly...perhaps. And two or three of those are "lost" to deadbeat "buyers", who either don't pay or insist on returning a cover (for hundreds of reasons) for credit, and these are now damaged or "used".
How many covers do you want to store and carry in inventory? And, for how long? (I don't have a good model for these costs, but they are non-zero.) Each cover boxed is about 16x10x4 inches, 640 cubic inches, or 0.37 cu feet each. Floor footprint is 16x10. Can probably stack them 10 high without crush damage. For a space need of 1.11 sq. foot per 10 units of storage space needed. That’s' 1111 sq. feet of floor or shelf space and 370 cu feet volume space needed if 1000 covers are acquired for initial stock.
There are also packaging costs as well. Poly bag, cushioning materials, carton, labels. ~$5-6 each for low quantity? Perhaps half this for 1000 quantity buys.
There are different kinds of tooling materials used to make injection-molded parts depending on expected tool life. To make 1000 covers, you would need a steel tool. But, it won't have to be heat treated or hardened. Based on my experience, you could probably have this made for $25K-$50K for a simple 2 piece clam type mold.
You will also need a machine that heats the plastic pellets to proper temp and pumps the molten plastic under pressure into the tool. The machine also runs water through the tool to cool the mold and plastic part, opens the tool halves, ejects the part, and repositions the tool halves for the next injection cycle. For this small a run, you probably wouldn't buy the machine or the facility to operate it in. (not sure of the cost but over $100K comes to mind.) You would just contract with an existing injection molding outfit to make your parts. The actual plastic pellet costs per piece are probably $0.50. So, if you make enough parts, it's really cheap. But, you have to make enough, long term, to pay for your development and tooling costs. You also have to pay for material cost while you develop a recipe for the correct injection temp, mold temp, cool down time, and tool movement cycle time. These initial parts are scrapped, due to voids, sags, and other defects in the molding process. After the development work is done, then you pay for a production run of saleable parts. Some initial parts are waste as the tool gets up to and stabilizes at operating temperature.
Assembly:
The original Honda cover was made with a multi piece articulated mold in order to get the posts formed onto the back of the cover. Articulated multi piece molds for this process are way more expensive to tool up than the cheap two piece clam type one I estimated above about double. But, they pop out a completed part per cycle. The cheaper tool would have a feature cast into the molded cover to accept post inserts (which would also be molded in the clam). These inserts would have to be glued in with a separate operation. It is unlikely to be cost effective to build a machine for this. So, manual labor must be provided to assemble the covers, or, simply provide instructions for the end user to glue the posts in place,
For 1000 boxed covers ready for shipment:
$25,000 - Clam tool.
$5000 - part production costs (manufacturing facility and production time/operator, and plastic injection material.
$3000 - Part packaging materials
$1200 - Yearly storage of unsold covers. The clam tool has to be stored somewhere, too, as does the plastic pellets.
$34200- invested in for 1000 covers means that each cover is costs $34.20 to produce. If you are not selling each cover for at least $50 each, you're an idiot. And, even at that, you work for free (or a loss) until you've sold 684 of the covers. If you manage to sell them all you make $15800 for the year or about 46% ROI.
But, I think this is really an optimistic view. Tooling and production costs are likely to be much higher. That'll eat into that $15K really fast. And if you are even able to sell 500 of the covers, then you can probably sell ice cubes to Eskimos, too! You should stick to pure sales as a livelihood. And, leave all that unnecessary manufacturing and distribution issues to someone else.
I think that if you can't make and sell at least 1000 covers, tooling up for injection molding just doesn't make sense, even though the price/part can be quite low, ultimately.
For lower quantities and lower investment costs other methods can be used.
Plaster casting/mold, maybe a 50-piece part life before replacing the mold
Fiberglass molds- 100 or more part life?
Each finished cover will contain:
Resin $13.75/ qt. (Styrene monomer, Epoxy resins are double or triple that with hardener)
Catalyst $2.75/ 2 oz.
Fiberglass $7-9/yard ( Will Need a couple layers/ Carbon fiber is $45/yard)
I think there will be $20-$25 in materials in each cover not counting the mounting posts, which have to be engineered and somehow attached to the cover inside. (labor)
So, after the mold is cast, refined, polished and waxed 5-10 times, the cover can be laid up (about an hour) in the mold and allowed to cure 24 hrs. Then, remove from mold cut and trim part edges, and attach posts. When cured, the part can be bagged, boxed, labeled, and placed in inventory. (Storage/ shipping costs?)
Oh, making the molds will take 1-5 days development and labor, depending on type and quality. Suppose anybody would pay for this?
How much goes to the person who does lay up, assembles, inspects, packages and ships the cover?
Recently, I've been considering vacuforming also. But, this has some engineering challenges with mount post attachment, I haven't been motivated to solve. Especially when people are only willing to pay $15-$20 for a cover.
