Hmmmmm....I might have to RIDE this thing...

1660bob

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Hi All. After years of work, I have suddenly realised I have what looks like a Vincent motorcycle in my workshop, with little work now to complete.

I have to consider the possibility of actually starting and riding it sometime not too far ahead.......

Thus my thoughts turn to the practicalities, and the Girdraulic front end. Fully re-furbished, I have at present the standard springs awaiting fitment.In view of all the horror stories of tank slappers etc.is this a good idea, or are there alternatives?

I have fitted the Kawasaki damper, and I am totally underwhelmed by its apparent ,er, effect. On its lowest setting, the damper appears to have no effect whatsoever on the steering. With the front wheel suspended, the bars just clatter from side to side as if its not fitted, and clicking the adjuster up to max provides only very modest resistance and the steering still falls under its own weight, from side to side, hitting the stops a little more sedately. I cannot see how this could have any influence over the steering at all, it just seems woefully ineffective. Am I missing something here? Damper is new, and although stored for some time, seems OK, no leaks etc.

Here`s a few pics, progress so far, damper set up, and me smugly showing off my home brewed throttle cable fittings. You may note that my Vincent workshop also has a minor secondary role as a kitchen!!
 

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Bill Thomas

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Hello Bob, Like Bruce says, If you can show us the fittings, I thought you was building a chopper, Or was that another bike, Back to the Kawa damper, It does not have to have too much resistance, If it had, It would weave all over the place, I only use mine on 3 or 4 clicks, But it's all about leverage, Good Luck, Bill.
 

vibrac

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Thats the same damper we use on the racers -except we attach on the eccentric/spring box point so the leverage is higher but its still sufficent -you dont want to induce weave from a high resistance damper

a quick high impact push on the end is more representative of the forces you are trying to control
 

Bill Thomas

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It looks good to me, It does not take much to calm the steering down a bit. My Comet is super now. Nice Job. Bill.
 

timetraveller

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If you want some of the short springs I still have two left. One is the 'red', 75lb/inch, intended for use Comets but which turned out to be too weak for fully equipped road going Comets. The other is a 'white', 130lbs/inch intended for use on heavily ladened twins or outfits. Experience by several riders has now shown that a combination of these two springs, giving a combined mean rate of 102.5lbs/inch per spring, is about right for most twins. This is slightly weaker than the 'blue' springs which were also part of the original batch, which had a rate of 110lbs/inch. I have one outstanding order so a new batch of springs will be ordered this winter. These will have a rate of about 105lbs/inch and also some more 'white' springs will be ordered for the heavier bikes. If anyone out there would like to place an order then their request will be incorporated into the order. Price is expected to stay about the same as the first batch at £15 per spring. Coincidentally I have also been working on a simple system to incorporate a method for adjusting the spring preload which would be just about invisible but other projects have got in the way of final design and prototype manufacture. Noting that these springs are all approximately 100lbs/inch then it can be seen that an adjustment of only one inch can give an adjustable preload of 100 lbs. Once again if there is any interest please let me know.
 
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dave1949

Guest
Nice looking bike - I'm sure you will enjoy it. I finished a similar rebuild of my C Rapide this spring, and have been riding it through the summer. I also wanted to prevent tank slappers (although to be fair I had never had one before the rebuild). The first step was to renew all spindles and bushes and the steering head bearings, which I am sure you will have done. I had concluded that longer, softer springs with good damping was the way to go, and fitted a Thornton damper, with a Thornton spring on one side and a Series D spring on the other (a combination recommended by Dave Molloy of Thornton). I also fitted a Kawasaki damper as further insurance (which works fine, by the way). I also had a 21" wheel rim fitted so that I could use modern tyres (Avon Roadriders) at modern pressures. I put Petteford springs (1" longer than standard springs) and a Koni damper on the back. The suspension is now definitely more comfortable and compliant than it used to be, more like a modern bike, and the steering is very accurate. Result!
 
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