Hi. When I stripped the front forks of my 1960 Dommie 99 barn find, I found that each fork leg had two springs inside. There was the long spring that goes over the damper rod but there was also a short spring (see photos below) that sat inside the oil seal holder/ slider extension. When I look at my genuine Norton parts book it shows only the long spring that goes on the damper rod.
So are those short springs wrong? It looks like they’re wrong but I just don’t know - maybe Norton forgot to add them to the drawing in the parts book?
It’s almost as if a previous owner has got a pair of external springs (like you’d have on a cafe racer) and hidden them inside the fork tubes that screw onto the bottom yoke. However, I can’t understand why they would have done that.
Any ideas and opinions gratefully accepted. Regards
Is there any evidence of sidecar use? Just maybe the PO wanted a stiffer front end when hauling a chair? Or did he weigh 20 stone?
my first thoughts on it. I'm sure that it never left the factory like it.
Thanks George. There’s no evidence of sidecar use - the lower yoke is the solo variant not the sidecar one. I’m not sure what other frame-based evidence might indicate sidecar use but there’s nothing obvious. My main concern was that if I left the small springs out, I’d be doing something wrong. I’ll dump them in my ever-expanding box of oddities that came with this bike and just fit the long springs over the damper rods.
There are in some part lists, items listed that are not shown in the drawings. So you need to read the list carefully.
E.g. in the -59 list, the paper washer T1049 under the oil seal is not in the drawing.
Long roadholders had external springs inside the shrouds, I expect the P.O. was trying to stiffen up the front end, however springs are funny things, basically being a line of levers. If you put two springs of equal rating side by side you double the effort required to compress them, if you put them together, ie one on top of the other you halve it. I think these will be working as if they are side by side.
it always seemed counterintuitive to be that you could make a spring stiffer by removing coils!
Mikael, Good point - I’ll check the parts list carefully. Although as none of the Norton parts suppliers sell them for ‘standard’ bikes, I’m fairly confident that they shouldn’t be there.
Dan, thanks for the info regarding long Roadholders - maybe the previous owner was more used to those forks than short Roadholders - who knows! Interesting to learn about the way springs work - they are indeed strange when working together with another spring.