The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: paul.w on December 23, 2020, 03:24:51 PM

Title: Steering damper
Post by: paul.w on December 23, 2020, 03:24:51 PM
I said I'd soon find another problem, here it is.......

I've discovered my steering damper is loose - this is I guess why 60+ mph feels "nervous" (or at least, the rider does!).  I've tried tightening it and couldn't and I can't work out how to get it apart (I don't want to hit it with a bigger hammer).

The adjuster unscrews and i can take it out of the headstock (its about 12" long and threaded at the end) and I then expected the parts of the damper to fall off - but they didn't. There is about 1/8" of gap between the damper discs so obviously it doesn't work and it can't be tightened.  The bottom disc is loose and under it there is a boss which I'm guessing should be what the damper rod screws into and gets pulled up to apply friction. I expected that a gentle tap on the top of the rod would push this out the bottom - but it won't shift.  I don't want to hit it hard or put a rod down the hole and hit it in case I either damage the thread or break something.

I'm at a loss!  I'm missing something, how do  take the damper off the headstock to either replace the friction material  - or just to check it and then do the damper up a bit.  It seems to me the bottom boss should just drop out, is it just that its stiff and needs hitting with a bigger hammer (which I am loathe to do for obvious reasons)?









Title: Re: Steering damper
Post by: singleminded on December 23, 2020, 05:25:08 PM
The bottom fitting that the damper rod goes into is held in place by the bottom spindle.
Title: Re: Steering damper
Post by: Thomas on December 24, 2020, 07:42:06 AM
Hi Paul,

yes, 1/8 of an inch means that the damper disc is loose. To get the damper rod thread into the disc one needs to move the rod from side to side a bit until you hit the hole . There is no radial guide.

I do not believe that your loose disc is the reason for your  "nervous" driving. The damper is made for sidecar driving and should be untightened for driving without a sidecar.

Cheers, Thomas
Title: Re: Steering damper
Post by: Greybeard on December 28, 2020, 09:57:11 AM
Hello, Paul. At the risk of sounding flippant, if you wish to ride at 60mph plus is an 80-90 year old machine built up of many irreplaceable parts the ideal machine to use?  ::)
Whilst I'm sure the machines were capable of it there were times when worn out parts were more readily available. If the bike feels 'nervous' rather than the rider then I would be directing my attentions towards head bearings, fork spindles, wheel-bearings, tyres etc rather than on something that at best can only mask the symptoms of a problem. As Thomas has said, the dampers were primarily for sidecar use.  The dampers on my bikes are always backed right off and could just as easily be removed without causing a problem.

Steve
Title: Re: Steering damper
Post by: klaudius on December 28, 2020, 10:43:18 AM
Hi Paul
What fork levers are built into you. Is it the long ones for sidecars that reinforce the feeling when components are a bit worn out. Is the fork adjusted correctly? Relieved checked? I built something like this to relieve some of the pressure. Is from old wagons. Nice size from Germany. Claudius.