Last Monday I had big fun “trashing” the little twospeeder around an outdoor karttrack doing about 1.300 tight bends… And using low gear for 99% of the time….See pic.
And yesterday I took the Scott to a veteran bike rally and rode almost 400 km. And enjoyed every single one! And I just have to admit it over and over again… Scott riding is BIG BIG fun!
But I guess you already knew that…
Both on track as well as on the public roads my two speed gear occasionally slips. It happens both in low and high gear but not always. I have tried riding with much, less and almost no oil but cannot spot much difference. It happens mostly in low gear as if it takes a while to “grip”. Increasing preasure on the pedal seems to do very little. In high gear the gear occasionally “jumps” out for a second or two while riding. Not very often though but very typical…
I completely overhauled the two speed gear earlier this year converting to needle bearings in the drums and also needle thrust bearings. I ensured both expanding rings to be a good sliding fit in the drums. Made new hardened thrustplates etc.
I have not taken the gear to pieces yet. Might do so this winter as I intend to take the engine out anyway for a decoke and new gaskets (I know, I know, you can do that with the engine in the frame…). So I could inspect the gear too.
But does anyone have any idea on the slipping?
Ken Mercer here from Cape Town.
I cannot claim recent experience of two speeders but as a very young man my only form of transport was a 1930 two speed sports squirrel. This was also a lot of fun but as it was my only form of transport for getting to and from work and for all recreational purposes it did have some drawbacks! I used the bike for about three years before swapping it for a more user-friendly 1929 three speed tourer model.
I just wanted to say that although I had my fair share of problems with the gear I do remember that it did not slip in top gear. I remember also that the adjustment of the rod which controls gear selection was quite critical. The quick thread arrangement was I thought pretty basic and on my machine I had to compromise and accept that to stop the low gear from slipping I would have to hold the gear lever down with my heel if I wanted the high gear to stay put! I do recall that on one occasion the small end of one of the pivot bolts snapped off which of course resulted in lost movement and very little drive. I had to make replacements because in 1946/7 the Scott Co had almost no spares for two speeders and there was no Scott Club then either. I also had to have a complete hollow spindle made by a friendly tool-maker because some previous owner had butchered the threads beyond repair.
You have obviously done a great deal of work on your gear but in good order they should not slip if the actuating mechanism is able to hold the thing tightly engaged.
On one epic occasion I even rode the machine from East Essex to the Isle of Man to see the 1947 Manx G.P. and carried a pillion passenger all the way. I had absolutely no problem with the gear slipping and had to climb some pretty steep hills en route. We must also remember that Scott two speeders were raced with sidecars attached so the ability to drive without slipping was certainly there.
Maybe I am being silly here but have you considered that perhaps modern oils are just too darned slippery for this type of application?
No doubt one of our more erudite members could comment on this!
I look forward to hearing how you sort the slipping problem out.
Thanks for your reply. Here a few answers.
I also have adjusted my gear so I have to keep my heel on it in low gear but it will stay put in high gear. That works just fine.
The oil I use is a fairly old fashioned SAE 40. But more or less oil does not seem to make a difference.
Below a picture of the gear that I took when disassembling it for the overhaul I did last year.
In the yellow oval you see the rollers that enter the clutch rings. I swapped those for two of a somewhat smaller size so that they engage just after they pass the radius on the rings. In Technicalities this is considered of the utmost importance for a smooth and light gear operation. While assembling I already noted that with this rollers in place the thrust lever most touched the side plate behind the ring before expanding the ring fully. But that was by handpressure. Maybe by foot pressure thrust lever is just touching the pressure plate and that actually keeps the gear from engaging properly. But I should be able to see that on both side plate as the thrust lever.
Does this seem a feasible idea or am I talking nonsense?
I guess I will know for sure when I disassemble the gear. But that will be after I finished overhauling the engine of my 1912 Premier, also a very nice job I am currently working on!