Vincent damper. AVO damper.
- Thread starter john998
- Start date
Hello John,
The AVO dampers do not have hydraulic stops built in, and I am fairly sure this is also true for Koni and Thornton dampers.
I think it extremely unlikely that a damper rod would fail because of topping out.
I also think any significant topping out would be so uncomfortable (and dangerous if at the front) that the rider would soon take steps to correct the cause, and this would be true even if a hydraulic stop was present.
Turning up the adjustable damping (which mainly effects rebound) would provide an immediate reduction or elimination of topping out.
A broken damper rod is almost certainly due to the rod being forced repeatedly to bend sideways. For example, this could easily happen at the rear if the spacers F57/2 are too short so that F28/1 cannot rotate as the suspension moves. My own bike was perilously close to this, perhaps because of unfortunate tolerances or because of over tightening over the years. I know of one bike that had a standard Vincent damper rod fail at this point on the Isle of Man. Any seized parts would also do it of course!
I have to say I don’t like the way that D8 is locked with a pin through the rod on the original damper. It must weaken the rod considerably. Thread locking compound only for me.
Rob
P.S.
A shorter reply would be that it would have been a nice extra feature to have, but if the suspension is set up correctly, it is not needed.
Last edited:
David,
My Vincent damper has a hydraulic stop at full extension, and my Armstrong damper feels as if it has, though it's difficult to be certain. Both act over a very short distance though, so they only provide a limited cushioning effect.
I had a Vincent damper explode on full bump on the trials outfit going up a section on an MCC Trial when I hit a rock (bolder) at about 20. All the seals failed the oil covered the mudguard and handlebars but the rod, pin and damper top (D6) were all undamaged
Hello John, Yes I snapped the top off my front damper, At the end of the thread, On my outfit, In 1965, Cheers Bill.
Hello Bill,
Any idea why it snapped?
I know there can be a very big gap between cause and effect. The rear half shaft on my Lotus snapped when it was being driven by my wife who was very pregnant at the time. She stopped at a T junction and the back wheel and hub rolled slowly past her. Investigation revealed fatigue lines in the shaft that looked to have been spreading for a long time. As I know that corner of the car had been thumped in an accident before I owned the car, the initial crack in the shaft must have been started at least a decade earlier.
Rob
Hello hadron, No I was not Pregnant !! But I was Very Young, The throttle was like an ON / OFF switch, With low gearing and a third wheel, So i could not fall off !! I can still see the forks going up and down like a mad thing, I doubt there was much oil in the damper, Which could have been the cause ? How could it have been so many years ago !! Cheers Bill.I wonder if the link bushes were a bit worn?
With the extra side loads from the sidecar, the forks could have been moving about enough to bend the damper rod. No wonder later manufacturers all used metalastic bushes to mount the dampers. No alignment problems!
With the extra side loads from the sidecar, the forks could have been moving about enough to bend the damper rod. No wonder later manufacturers all used metalastic bushes to mount the dampers. No alignment problems!