FF: Forks Cadwell Landsdowne video + Suspension Setup

greg brillus

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A Comet with the stem kit, including the link bearing mod........A hydraulic steering damper, a pair of shortened 45 Lb springs and a soft shock of some sort will give the best riding Vincent you can have.........The only Vincent twin i have done where the front end was fabulous was the twin racer on my picture to the left.........This with the fully sprung rear solo seat and the back jacked up using one of the 270 mm coilover shock absorbers and a 300 Lb spring was amazing.........easily out turn any Featherbed racer........Bill you mentioned the Spax shock........I had never seen one until recently and they do appear to be a really great shocker.........nice soft action and adjustable........ But yes the welded on ends look horrible......such a shame........They would have worked very well i think on these bikes.........The big down side to jacking the rear is the drive chain looks like it will fall off, well until you sit on the bike and push it into corners..........Remember to with David's springs, they go in with almost nil pre load.........The springs for the stem kit do need pre load but not much, certainly with the 45 lb ones I have done..........I have 4 bikes in the workshop all 4 with the modified front end..........One Rapide, 2 Touring Shadow's and an enclosed 'D" Prince..........seems to work well on them all.........
 

Bill Thomas

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It's all a bit too much money and work for me Greg,
I don't go very fast now, Well not often !, I would rather spend what money,
I have on other Bike, Things.
 

Wad

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Well we were down on power we still got a 1st in our class on Saturdays race but the silencers need to be revised, this is Sundays race the camera is positioned to examine the forks performance (Norman will no doubt be interested) I guess it needs harder springs but looks deceive it handles very well. There were two missed gear changes the first one was a tour of the grass infield (you need engine breaking coming down the mountain!) the other was a lot over 6K and the result was silence. as I said in my bit in MPH that tee shirt said it all "Race Break Mend Repeat!"

Got to say that was a very exciting video, the handling looks good and the engine sounded really nice.
 

brian gains

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"Got to say that was a very exciting video, the handling looks good and the engine sounded really nice."

great video but made me realise that by comparison my motor sounds like a fire in a pet shop particularly since fitting the steel idler. Also made me think mav be the Comet could do with softer springs and that's having recently removed inner springs fitted by PO.
 

timetraveller

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It's not just softer springs. It is the whole JE stem conversion, with ball races in the rear of the lower link which is needed, preferably with a hydraulic steering damper.
 

erik

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I mounted the inner springs ,too. On one side i shortened the inner spring 30mm and on the other side 40mm Shorter than the outer springs.I tried to do something like a progressive spring. What do you think?Erik
 

timetraveller

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I remember discussing this with someone a few years ago. Possibly it might have been you Erk. I have forgotten the rate of the inner springs but if they were shortened then the rate would have increased anyway. I think that the concept might work but it is possible that softer inner spings might be needed to get the best out of the idea. If anyone wants to try this then I could get some suitable springs made but we would have to discuss first what strength might be needed. Using the 36 lbs/inch springs as an example, these are 16.5" long and are installed with a three inch preload giving 216 lbs force, from both springs, before fork movement. Suppose you want the extra force to kick in after the first inch of movement then the inner springs would have to be 12.5" long and after the first one inch of movement the rate would go up from36 lbs/inch to 36+ whatever the smaller spring rate was. Suppose they were 10 lbs/inch then the rate would go up to 46 lbs/inch which is roughly the same as the strongest spring I have provided at 45 lbs/inch. If anyone want to discuss this on here then if there is interest perhaps we can experiment. I could do some calculations and plot some graphs if that would help.
 
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