This info taken from a posting, check his website for more info...These codes also can be found on my web site: www.fortyfour16design.com.
Previously, I wrote that a frame with the SN on the BB was made prior to 1980. As I collected more SNs, I began to question this theory. I now believe this is incorrect. Indeed, Torker used the SN on the BB early on, but it used it until mid-1980. From about that time, depending on the model (but there is no obvious solid date) the SN was put on the right, rear dropout. Using the SN location to date your frame should be avoided.
I've been collecting Torker SNs for a few years now. A few months into it, I had a theory on how it worked month-by-month. At the time, however, I overlooked a few details and couldn't make my theory work. I also had a few odd-ball numbers (still do) that exist due to: 1. Misread/inaccurately reported SN; 2. Poorly stamped SN; 3. Factory Mislabeling; 4. Unreadable SN; 5. All of the above.
As it turns out, my first theory was dead-on. Those few odd-balls not withstanding, I'm 90+% sure I've cracked the code from May 1978 when the Low Profile and Big Bike production began to October 1984 when the original U.S.-based company went bankrupt.
Prior to May 1978, Torker seems to have used the "standard" BMX SN system that many companies used. I have only two SNs from that time, but am pretty confident of how they work. They look like this: T877188 and T977270. My best guess: "T" for Torker, month (August and September), year (1977), frame production number (188 and 270).
Starting in May 1978, Torker went with two letters (T? or ?T)—a "T" for Torker and a second letter corresponding to the month of production. The first letter in the series is "A" for May. Next is the production number of the model. The final letter represents the frame model. For example: TJ 3344 L = February 1979; the 3,344th frame in the model series; "L" for Low Profile (L.P.) or, The 3344th L.P. was made in February 1979. One caveat to this is if Torker used a letter to identify the model through 1978. I only have two SNs from 1978 and neither has a final letter.
The first series starts with "TA" in May 1978 and ends 26 months later in June 1980. In July 1980, the new series starts with "AT" and runs 26 months to August 1982. The model production numbers continue sequentially through both systems.
In September 1982, Torker switched to a new system starting with three letters TZZ to TAA. Around this time, Torker also changed its product line, dropping or changing all previous models and/or names. For example, the L.P. was renamed the 280 and all mild steel models were eliminated. The SN system, however, remained the same, with the exception of the three first letters and that it started at the end of the alphabet rather than the beginning. For example: TRR 8122 = May 1983; the 8,122 frame in the model series; no letter for 280. Frame production numbers started over from "1" with "TZZ."
Most SNs end with a letter. The letter identifies the model. Those SNs that lack a final letter are either L.P.s or 280s, depending on when the frame was made. Torker dropped the "L" when it discontinued the Big Bike (B). At the same time, Mild steel L.P.s went from LM to M.
My research is only on the frames made by Torker in its own factory in Fullerton, CA, USA. I do not have any research on frames made in Asia after the Oct. 1984 bankruptcy.
I must thank the guys who put together the Haro frame registry. Their work made this job much easier.
are the date codes followed by the model ID codes:
B = Big Bike (from May 1978; had rear-facing dropouts; previously the MX)
BM = Mild Steel Big Bike
E = Eddy King Replica (European BB)
L = L.P. (Low Profile)
No Letter = Standard L.P.
LM = Mild Steel L.P. (1978-1979)
M = Mild Steel L.P., 1980+
0 (or O) = Long L.P. (has longer top tube (19" )
0M (or OM) = Long Mild Steel L.P. (has longer top tube (19" )
No Letter = Standard 280 (from Sept. 1982)
0 (or O) = 280 Long, (has longer top tube (19" ) (from Sept. 1982)
0X (or OX) = 280 Long (has oval-hole gusset and 19" top tube) (from some time in 1983)
P = Pro XL, late-1983, (has longer top tube (19.5" ), Haro/Redline-style gusset, butted tubing and 1 1/8" down tube)
SC = 24" cruiser (Small/Short Cruiser)
C = 26" cruiser (Cruiser)
R = Mini
RP = 1984 Mini Pro (Only known frame belonged to Factory Torker rider Craig Bark)
F = Haro frame (Freestyle?)