Subject:RE: RE: RE: RE: exhaust for K 1920 steve and cylinders Date:Wed Dec 17 22:22:41 2008
Response to:2230
I did notice the cylinders were the "stubby cylinders" I also like the one person wrote purchased new manifold nuts to find out they were like the 1938-42 indian four ones too long. What I really wanted to know although you did teach me a few things I did not know and again wish you were close by when I did mine so we could see each bike up close... I wanted to know as I had been told the frame of the motorcycle was diffrent from the 1921,22 long tank models. what actually makes it a 1920 frame only?
M.Kane told at one time but he said he had heard there was even more diffrent.I see that we have opened a great discusion according to how many people have written in! I want to say I have always noticed the Henderson comunity has always been nothing but helpfull!!

Hi Pat - always pleased to help where I can.
The 1920/21 Model K cyclinders were different to the Deluxe. They are very similar but if you put the Model K next to a Deluxe some of the differences are pretty obvious. If you picked up a cylinder from one model at a swap meet, it may not be so obvious if you had nothing to compare it to - and it won't fit on the other model! Here are the differences:
Base flange area is the same so either will fit on the other case but the flange itself is only 5/16" thick on a K compared to 13/32" on the Deluxe. Inlet/exhaust port bores are smaller on the K - 1" dia, DeLuxe is 1-1/8". More importantly the stud spacings are smaller - K=1-23/32", DeLuxe = 1-15/16" - so the inlet/exhaust manifolds don't interchage. The finning is also different. Both have the same number of horizontal and vertical fins. The Deluxe has longer horizontal finning around the exhaust port area. The real giveaway is the fin pattern at the top of the cylinder. The K has 6 vertical fins on the top horizontal fin plus 2 more vertcal fins on the second horizontal fin. The Deluxe has 4 vertical fins on each of the top two horizontal fins. Valves and combustion chamber shape on my K cylinders are the same as that on my Deluxe cylinders so I assume the Deluxe cyclinders are early ones. (There's info elsewhere on this site about different combustion chamber shapes too) The thread for the valve cap is the same though the caps themselves differ - The K has four low height 'fins', whereas the Deluxe has six taller 'fins'
All dimensions given are give or take a bit so please don't quote me on them!

Also, the early factory literature on the Model K show a round exhaust port stub. I understand a few were made before it was changed to the flat 2 stud flange we are all familiar with.

Hello Steve I did not know they were not interchangeable I was always going to swap my "stubby cylinders" for the Delux ones have you tried to change them? I never did they looked somewhat the same. By any chance do you have a spare set of Delux cylinders you could put on your motor and try out? I always wanted to know as I repiared one of my cylinders and what a job and a half that was. I wish we would have written back and forth when I had mine.

Hello Gorm
The 20/21 Henderson exhausts didn't have the long downpipes - they didn't come in until the width of the frame was increased and the motor fitted on forgings rather than fitted with bolts doing through the frame tube iteself. Model K's were fitted with a cast iron manifold which tucked in under the carburettor. Early 1920 machines had circular flanges onto the cylinders but quickly changed to oval flanges similar to those on the later DeLuxe. But note that the stud spacing on the K's was less that the DeLuxe so manifolds/cylinders are not interchangeable inless you swap the whole lot (including inlet manifold and carb!) Hope the picture helps

Looking for drawings, pictures for exhaust profile for Henderson 1920. The sales brochures 4 tubes going down must have a very close passage betwin frame and engine. Looking forward to have profile for those - trying to make repros.
Thank you.