1920 Model K
Steve Marks
United Kingdom
steve@microdesign.ltd.uk


July 12, 2007
After fourteen years work (not continuously of course, I had weekends off....:-)) The big start up day had finally arrived. Kicking her over was difficult. The engine was tight and every time I kicked down, the back of my leg hammered into the edge of the seat Ė boy have I got a bruise! It fired pretty well every kick but I could not get it to pick up. Just not able to turn the engine fast enough I think. The audience(!) persuaded me that I should try bump starting it so with plenty of volunteer pushers we set off down the yard with second gear engaged. As soon as I dropped the clutch it fired and continued to fire but wouldnít pull away. We ran out of room so had to stop. Next time down the yard I dropped the clutch and again it fired straight away. This tme, I pushed the clutch pedal back down and she was away!

Oil presure was good, response to the throttle was pretty good. Have to admit that moving the advance/retard didnít seem to make a lot of difference but then it was stationary with no real load on the engine. After a while the paint on the cylinders and exhasut pipe started to smoke so I cut the engine. Even that short run seemed to free up the engine Ė once it had cooled down, it kickstarted with no problem. Then someone suggested putting it into gear and going for a ride. I was thinking of quitting while I was ahead but hey - what the hell!

Clutch down, gear lever forward and away we went. But a bit of a disappointment Ė it didnít seem to want to pull. The engine almost stalled and I had to dip the clutch, pick up the revs and engage the clutch again. After several dips of the clutch we were away but a lap of the yard showed that the engine was reluctant to pull cleanly. I stopped and put it into neutral. Throttle response when stationary was getting better and better. Anyway, at least she was running! There were a few cheers and we broke open the beer cans. A non-motorcyclist amongst us asked what all the levers were for so I went through them all until I got to the last one. ĎThis is what is called the emergency brake. It can be locked on a bit like a carís handbrake.......í Thatís when I realised it WAS locked on...........

So, with the emergency brake OFF, I started up again and had several laps of the yard in first gear with no problems! Having that brake on probably also explains why it wouldnít drive away on the first push, especially as it was in second gear as well.

Next day I went off down the road and did about a mile and a half. Yes there were a few things that needed doing. The valve caps leaked. I had used Holts Fire Gum with the copper ring washer but it wasnít too successful. Resealed using Permatex High Temperature RTV silicone which has been OK since.

The rear stand fell out of itís catch and dragged along the ground. A plastic cable tie did a temporary repair followed by the touch up paint(!) The gear change needs looking at. I can adjust the connecting rod and get first gear but not third. If I adjust to get third, then I canít get first. And I had been so careful to get the hole for the front clevis in the right place! Looks like Iím gong to need to drill another one higher up the lever.

More short rides out with my son Andy following me showed that, not only did the speedo work but it was pretty accurate - at thirty mph at least! Kickstarting now is no problem. I can stand further forward and kick backwards rather than down so my leg now misses the seat. The engine is much easier to kick over. I more or less just straighten my leg and she fires up easily Ė no real effort at all (not compared to a Velocette anyway!) Iíve done about ten miles so far and one thing I do need to do is lower the gearing. Itís fine in first and second but is not comfortable in top. The Deluxe parts books list 15, 16 and 17 tooth engine sprockets so when it was time to make them, I made one of each. Then I fitted the 17 tooth sprocket on the basis that it was easier to fit a smaller sprocket and shorten the chain if necessary rather than go bigger and try to lengthen the chain. What are you other Model K riders using on the front sprocket?

A special thank you to all you guys out there who have helped with answers to my questions and sent photos of bits Iíve needed to make. Apart from the technical side, the moral support and encoragement has been great as well. There have been too many to name individually (and I would hate it if I inadvertantly left anyone out) but you know who you are Ė thanks a lot. Having said that I feel I must mention Rob Olsen. Apart from the technical support both through this site and directly, I feel I must mention his clutch kit. When I put the bike into first gear from a standstill it is so easy Iím not even sure if itís gone into gear Ė but it has. Changing up is silky smooth too. Changing down is a bit crunchy sometimes but Iím putting that down to rider error and with a bit of practice Iím sure itíll get better. Iíve ridden several different fours before, including Indian and Ace, and know all about clutch drag and crunchy gear selection. No problem with this set up though Ė highly recommended. Thanks Rob. Tied up with the clutch operation is the oil I guess. I know this has been covered before but when I took the advice offered and went shopping, the oil I wanted was not available in the UK. Many hours (maybe even days) research into what was needed led me to the conclusion that two things were important. First, the oil needed to meet the JASO MA specification which indicates that it is suitable for wet clutch and combined engine/gearbox applications. Second, it should have zinc dithiophosphate (ZDDP) - an anti wear additive - in the oil. I wonít go into the reasons why we need it in a Henderson engine Ė if you have an hour or two to spare do a Google search on Ďzinc camshaftí. I chose to use Castrol GP 4T (mineral 20W-50) for running in. Itís far too early yet to see whether itís the right choice but I thought some of you might be interested.