I've watched a lot of stock Ironhead Sportster frames on ebay come and go at prices ranging from as little as $100 to as much as $600 and more. Assuming the frame is unmolested, the listings that consistently bring the most money are those in which the model and year are clearly identified. If you want to get the best possible price for your frame, you should let potential buyers know exactly what they're bidding on. Of course, some builders will be happy with any compatible frame, but restoration types like myself need to know the specific model and year.
The two models in question are XLH and XLCH, and it's easy to distinguish between the two. On the neck web of an early Sportster frame you should find a casting number. If this number ends in -56 you have an XLH frame; if it ends in -58, you have an XLCH.
Another way to tell an early XLH frame from a XLCH frame just at a glance is by the seat posts. On the left seat post of an H frame there are two bosses for mounting a coil, and on the right seat post there is a bracket for the oil tank. On the other hand, the seat posts on a CH frame have no bosses or brackets.
Identifying the date of manufacture is fairly simple as well. If you look under the seat casting on the right side where the rear tank bolt would go through if you were running the large tank, you should see a one-letter-one-number date stamp, for instance C 5. The letter indicates the month (A = January, B = February, and so on) and the number indicates the last digit of the year, so if a frame's has the date stamp C 5, it was manufactured in March of 1965.
In an earlier version of this guide, I stated that if the order of the number and letter are reversed, the frame was made in the fifites, and that a 7 G frame, for instance, would have been manufactured in July of '57. This appears to be incorrect, and I apologize for any misinformation I disseminated (plenty of that going around already). It turns out that with the introduction of overhead valve Sportster in 57, Harley went to the letter-number format, so a C 7 frame could be either a 57 or 67 frame. You can distinguish the 57-59 frames from the 67-69 by the seat castings, which are quite different.
Usually a builder with a '65 engine wants either a '65 or late '64 frame, as Harley sometimes used frames from the previous model year to build the present year's bikes.
In 1967, Harley introduced the first electric start Sportster (two years after the Electra Glide). Only the H model got the upgrade, and in order to accommodate it, the seat posts had to be modified to make room for the electric start motor and a much larger battery. If the frame has the kick-back in the seat posts, it is a 1967 or later H model.
In the1970s Harley started putting the VIN on the right down tube (from then on the bikes were titled by the frame instead of the motor). If your frame has a VIN on the frame, it was made in the seventies or later and is easy to identify.
Finally, a note about K-model frames. The easiest way to tell if you have a K or KH (52-56) and not a Sportster frame at a glance is to look at the top motor mount bracket, also called the "engine steady." The Sportster Bracket (from 57 on) is made from stamped steel and looks like an open-sided box. The K and KH-model bracket is a cast piece and is open to either side (thank you, French Owl).
I hope this helps those of you selling frames. If you accurately post the year and model, it will definitely help those of us who want to buy them.
Thanks to my friend Magneto Sportster for his help in compiling this information.
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