Mass Produced Aftermarket Frames
There are basically three different ways to obtain a frame for your scooter project. The first and perhaps easiest is to simply buy an existing cycle and strip it down using the stock frame as the basis of the new bike. The second way is to buy a pre-manufactured frame from any one of dozens of aftermarket frame suppliers and the third way of course is to build your own chassis from scratch.
The advantages of the first method are many since you already know that the components will fit the chassis, the bike already has a title and registration and you know in advance how the original motorcycle handled. Within reason you can still ride the bike as you're making modifications so at least you can have a ride available instead of being car-bound for a couple of months. Modifying an existing bike is usually far more economical and significantly less complicated than building from scratch.
Using a pre-manufactured frame saves time but is typically more expensive than modifying a stock chassis or building a new one from scratch but like using an existing bike at least you have some legal paperwork to take to the DMV when it comes time to register the finished product. The vast majority of custom motorcycles today are built around these aftermarket frames and in fact many of the so-called 'custom' builders have never built a frame in their lives and instead use frames provided by the same suppliers that you and I have equal access to. This kind of makes me wonder why they call themselves 'custom builders' to begin with but we'll talk about that later.
When it comes to selecting a manufactured frame we have an almost limitless range of styles and types to choose from. There are hardtails, soft-tails, swing-arms, lowboys, stocker replacements, high-necked chopper styles, racers, bobbers, classics, antique reproductions and so forth.
There are as many manufacturers as there are available styles and types. Many mass production fabricators have been in business for decades while others tend to come and go resurfacing under new business names every few months or years depending upon how well or how poorly they have been doing. There are big fabrication concerns doing thousands of frames every year but there are also hundreds of small fabrication shops across the country doing both production and per-order custom work as well.
I've tried to gather production figures from several of the big concerns but nobodies talking. Unofficial sources however estimate that worldwide there are over one million frames sold each year for Big-Twins alone and that for every unit sold at least one other goes into warehouse inventory somewhere so the chassis business can be financially rewarding for the larger manufacturers. I know of one relatively small six-man operation that builds over 1900 frames per year, which works out to 8 per day, and they have an eighteen-month backlog of orders. In case you're wondering this production run puts them into the three million dollar a year business class.
I have personally built several bikes over the years using frames from Paughco, Santee and Daytec with mixed amounts of what I would consider to be satisfaction with the experiences. I've found that the overall level of quality and accuracy can vary considerably even between what appear to be identical frames from a single maker. Sometimes you get the best chassis delivered and other times you might get one that's not quite up to par so I strongly suggest that you spend a considerable amount of time looking into the purchase of a pre-manufactured frame even from the big name manufacturers.
Be especially cautious of products being offered by second tier manufacturers, re-sellers, distributors and wholesalers. Like everything else in life you get exactly what you pay for and a discounted bike frame is discounted for a reason. There are huge warehouses full of bike frames being sold under a wide variety of trade names and very often the Manufacturers Statement of Origin comes from a wholesale company and not the manufacturer itself. Many if not all of these frames are being made overseas and in Mexico or in chop shops in Southern California using unskilled workmen, substandard equipment and sometimes even with marginal materials.
If the reader makes a brief search of the Internet cycle forums you will find hundreds of posts concerning alignment and measurement problems with a host of manufactured frames and another hundred complaints about after-sales service, poor welding quality, rusted merchandise and a host of other reported problems so remember that for every problem posted there are probably another two or three that never get publicized.
The most common complaint is about the motor and transmission mounts being out of alignment and the bolt patterns not matching the cases. The second most common problem is bearing cups being either to large or two small for the correct bearing races in the steering neck and soft-tail swing arm pivot bores. Down the list are typical problems of the frame being twisted so the rear axle and steering head are out of square. In a dozen or so cases I've read in just the past two months there have been reports of weld failures and one multiple fracture failure of a very expensive name-brand aluminum chassis.
To explain why such problems occur in the first place one has to understand the environment where most mass-produced frames are built. Consider the typical medium size fabrication shop employing six welder/fabricators, a couple of helpers, a shop foreman, the plant manager and administrative support staff. All of the tubing is still cut and mitered by hand even if the shop uses state of the art machinery. All bends likewise are done by hand even if the bender itself is hydraulic. Lets say the shop has three frame jigs each with slightly different inaccuracies or peculiarities. Half of the staff don't even own a motorcycle and could care less about them since they're just there to pull down a paycheck. One welder is really good with ten years of experience; another is almost as good but rushes through his daily quota so he looks good to the boss. The other four guys have varying skill levels, the junior man on the team is basically just learning so all he does is tack frames up. Problems most likely start with the guy doing the mitering and bending. If his work is not consistent small errors creep in all along the line as the welders try to compensate. The welding itself ranges from excellent to marginal and don't be surprised to see obvious signs that your frame was not put together by a single welder as different connections are used as training for less experienced staff. Frames made on Wednesday will probably be a lot better than frames made at four in the afternoon on Fridays or eight in the morning on Mondays. Everybody is under pressure to perform as the foreman has production quotas to meet every week and cost-cutting measures are seen everywhere. Grinding wheels have to be used until these is nothing left but the metal hub and God forbid if you're caught snipping off an extra eighth of an inch of bent welding wire.
To make a long story short we have to face the fact that these mass-produced frames are not as identical as many would believe. They are each one made by one or more individuals with different skills, talents and capabilities in plants and shops that range from well managed and modern to sweat shops in back alleys or over the border.
After saying all of these bad things about store-bought frames you might think that I don't care to much for such products but in fact I think that one can indeed get good quality if you shop around and inspect the products with you own eyes before shelling out your hard earned cash. I would never under any circumstances buy a frame via the Internet or through a mail-order catalog.
There are well over six-dozen frames in the picture below. How many do you think are exactly alike and have absolutely perfect mount points, tight miters, deep penetration welds and perfect alignment in the axle plates. Would you accept the sales clerks word for their quality or would you want to hand pick one.
After the mass-produced frame there remains the true customized, made to order, hand crafted frame produced by the small individual fabrication shop or custom bike builder. As a general rule these frames exhibit the highest quality but they also cost more than their mass-market counterparts but not very much more. In some cases small custom bike shops have a line of semi-custom frames that can actually be less expensive than the big-name mass-market products so it may pay to search out builders near your geographical location. Unfortunately these small fab shops are fading fast under the pressure of economic competition brought to bear by the big manufacturers on one hand and the demands on their time being made by an ever growing number of customers wanting basis bike repair and minor alterations which leaves little time for frame building.
The frame is the single most important part of the bike but many people seem to forget this point.
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