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“What Fits What” Critique
by Jeffrey Diamond |
Many years ago, Mike Arman published a modest booklet entitled “What Fits What”, which purported to be a general guide to interchanging Harley-Davidson parts 1936-76.
Unfortunately, the number of errors is astounding. Many require the author to not only never have worked on one of the engines in question, but never examined a photograph.
My copy is an early version, bought in 1976. In the belief that my copy had already been superceded by a corrected version, I wrote to him offering some corrections.
Rather than consider my comments, he was patronizing, rude, arrogant and dismissive. I pointed out some enormous errors (over 100), and his responses were:
1. I’m wrong, there are no mistakes
2. He already knew it was wrong
3. It doesn’t matter if it’s wrong, nobody cares
4. I have no future in the business because my attitude is bad
Some of the mistakes are truly of biblical proportions, and could only be made by someone who had never actually seen any of the parts. Here are a few direct quotes and paraphrases, taken from the book:
Page 2: flatheads built 1909 to 1973. Actual date: 1926
Page 2: the last numbers, always four of them, are the sequential production number. 5 numbers, e.g. 47FL12629, are common in many years.
Page 3: he frequently refers to the 1st year of the 45” “W” engine as 1936 through 1951. It’s 1937 through 1952.
Page 4: the 1932-36 Servi-Car with the “R” engine had an “R” VIN. The 1937-39 with the “W” engine had a “W” VIN. 1940-73 Servi-Car with the “G” engine had a G VIN.
Page 5: the bore of the 80” SV is 3-7/16” The bore size of the 74” VL, 80” VL, and 80” UL is 3-27/64” or 3.421875”.
Page 16: the first pressure oiled 45 model in 1936. All 45 motors had pressure oil. They had pressure return beginning in 1937.
Page 16: 45 guide blocks have 3 mounting holes. They all have 2 holes.
Page 16: ... use the Fairbanks front mount magneto. It won’t fit, won’t turn, and if it did the spark would only be correct every few minutes.
Page 17: KH cams fit Sportsters. Only for a few minutes before they’re destroyed.
Page 17: Re: K vs. Sportster: the pitch of the primary chain is different. The K chain is shorter than the Sportster, but the pitch of both chains is the same as the 45: #35.
Page 18: KH cams have .175” more lift than Sportster. It’s about .100”.
Page 19: K heads will fit a KK but not a KH. Although the compression ratio will be wrong, all heads have the same bolt pattern.
Page 20: there are 8 types of cylinder/cylinder head sets. The older type has 9 head bolt holes and the newer type has 10. Both types come in either iron or alloy.”. There is only 1 head-bolt pattern for all UL & 1937-48, also used on the 1936 VL, with 9 bolts. There is no 10 bolt head. All 1930-35 VL is 7 bolt.
Page 20: the UL compression ratio is stamped on the side of the head. Only 45s are marked his way. UL motors have the chamber volume in cubic inches, e.g., “8.2”.
Page 20: the 1936-47 knuckleheads used a stepped pin. Only 1940-47, the 1936-39 used a smaller straight pin.
Page 21: 61 flywheels are smaller than 74. Only 1936-40.
Page 21: knucklehead bolt thread is 7/16-24. It’s 7/16-16, same as 45.
Page 21: how to put pan barrels on your knuck, just like the rubbish that appeared in Easyriders. What’s wrong with it? The pan barrels are .200” too short, the motor won’t even turn over without the piston hitting the head, bending valves etc.
Page 26: the panhead Timken sprocket shaft is 24001-56 and used since 1955. There is a different 1955 shaft with no collar, required a different left flywheel.
Page 26: oil drains through the case through 1954. It’s 1952.
Page 28: the left flywheel is the same 1955 through 1977. There are 3 used: 1955 only, 1956-71, and 1972-81.
Page 31: pinion bushings are the same 1948-53. It’s 1936-54 (he corrected it on Page 33).
Page 32: 1948-54 tappets were solid with hydraulic pushrods. It’s 1948-52.
Page 33: cams interchange 1948-69. 1948-57 cams had a bronze bushing, 1958-* had a needle bearing and different journal size.
Page 35: oil pump drive gears are all the same 1948-76. Same 1936-72 with 5 teeth, and different from 1973-* with 6 teeth.
Page 37: all transmission parts interchange 1936-64. The 1939 is different.
Page 37: 74 & 80 SV transmissions are different from OHV. Same thing.
Page 39: the 45 solo transmission is a 4 speed. None ever made, they’re all 3 speed.
Page 40: flathead frames are different than OHV frames. Same thing.
Page 41: this is a 45 frame - surprise!. It’s a VL frame.
More later... |
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