From:	Steve Marks	e-mail:	steve@microdesign.ltd.uk
Subject:	Model K differences	Date:	Wed Dec 17 15:34:02 2008

All the other postings were getting a little disjointed and I wasn't too sure which of them I should 'respond to' with this little lot...... I have a Parts List covering models 1918-1923. It is split into three sections. Models H&Z 1918 and Z-2 1919 Model K 1920-1921 Henderson De Luxe Model so our current Model K topic sits squarely in the middle. In the Model K section..... Only one cylinder is listed - Part No K-1700 Only one inlet manifold is listed - Part no K-1720 Only one exhaust manifold is listed - Part no K-1803 As expected, DeLuxe part numbers for the above items are different (KD1704, KD-1721 and KD-182 - the latter being described as 'Exhaust pipe assembly complete'- presumably all one piece?) You might think that this implies there were no changes during the 1920/21 Model K production but this is obviously not true - some of you guys have different variations and photos/drawings to prove it! This is backed up by a factory brochure I have which is headed 'Motorcycles for the season of 1921' and says ' A year ago when the Henderson Model K made its first appearance.....' and then lower down the page says 'Minor details, such as intake and exhaust manifolds....have been given equal attention with several improvements in operation and convenience'. The sectioned drawing of the model K in the 1918-23 Parts List shows the 'high' cast iron exhaust with flange mountings. It also shows a priming cup on the top of the inlet manifold - and yet in the 'Gasoline tank and fittings' section the Priming Gun valve is listed as 1920 - not available in 1921? I reckon, the drawing shows a late 1920 sectioned engine. Elsewhere in the Model K section, there are large numbers of parts which are listed as '1920' with an alternative part listed as '1921' I wonder - were the round port cylinders made in such low numbers that they didn't justify a seperate entry? My conclusion is that the cast iron exhaust pipe with it's seperately listed 'Exhaust rear vent tube - Part no K-1874' came in fairly early in 1920 and stayed until the DeLuxe replaced it with the one piece exhaust system. On the subject of frames and mudguards, the 1918-23 parts book lists the 1920/21 frame as part no K-500, rear mudguard is part no K587. The DeLuxe section in this parts book lists engine parts only so we need to go to the 1923 DeLuxe Model and Sidecars Parts List. 'Frame (Old style) K501' and 'Frame (New style Low saddle position) K502' are both listed. Rear mudguard has two entries: 'Old style for machines with high saddle position' - K574 and 'New style for low saddle position frame, will not fit old type frame with high saddle position' - K-575 So... three different frames, three different rear mudguards. This agrees with what we know - first K frame with engine mounting bolts through the frame tube, followed by the wider high, then low saddle frames. But that raises another question. If the wide, low saddle frame first appeared in 1921 as a Model K as Steve C suggests, why is it not mentioned in the 1918-23 List? (Sorry Steve - I'm not disagreeing with you - oh no no no - just asking the question) The frame would have been around for several years before the list was printed. It was a major difference so would, surely, justify an entry. They did list some parts which were considerably minor in comparison - how about the screw which holds the handle bar sleeve in place - the one in the end under the rubber grip? The one listed as 1920 is described as 1/4-24, the one listed as 1921 is described as 1/4-28. Apart from the thread, we can deduce that it is a different shape too because there is also a 1921 'Handle Bar Sleeve Screw Spring' listed but no mention of a 1920 spring! While looking at the frame/rear mudguard setup, consider the following: In the 1918-23 Parts Book, there is a 'Rear mudguard saddle K5877' listed as 1920 and a 'Rear mudguard and saddle support K5812 listed as 1921. In the 1923 DeLuxe Parts Book the same number - K5812 - is used for what is described as the 'Saddle Spring Support'. I think its fairly common knowledge that the K mudguard saddle was bolted to the frame using a 'hole through the frame' technique whereas the DeLuxe uses a pair of U bolts. Did the 1921 saddle support (same part number remember) use the DeLuxe U bolt method? Interestingly, the DeLuxe Parts list shows U bolts nuts etc - no mention of them in the K parts list...... So what does all this tell us? It tells me that I've got a hell of a headache...........