Author Topic: Mark Front Forks Question  (Read 363 times)

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Offline isettaman

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Mark Front Forks Question
« on: 19 Jul 2019 at 08:37 »
Hi All
I am missing the two "Abutments for spring" , item 34, plate 24, for my re-build. Does anyone have spares or the dimensions so I can make my own? Presumably the thickness could be crutial as it will affect the compression of the springs.
Any help would be most welcome.
Thanks
Dave

Offline phil1

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Re: Mark Front Forks Question
« Reply #1 on: 21 Jul 2019 at 08:13 »
Hi Dave
 I have recently done restoration on my mk.v and looking through my scribbled notes have found some front fork notes witch may be of some help, spring length 10 1/4" long etc. Regards Phil. 

Offline isettaman

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Re: Mark Front Forks Question
« Reply #2 on: 21 Jul 2019 at 18:38 »
Thanks very much, Phil
I have since discovered that they are actually stuck up at the top of the fork tubes and that's where they will stay.
Thanks again
Dave

Offline eddie

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Re: Mark Front Forks Question
« Reply #3 on: 21 Jul 2019 at 19:32 »
Dave,
           There were 2 types of spring listed for the Mark series machines - normal springs that were taper ground on the O.D., and heavy springs that were the same diameter for the full length. If you look at the parts book, it shows the taper spring fitted with the large diameter to the top. Now, the taper effectively makes these springs multi-rate, and the general rule is that multi-rate springs should be fitted so that the 'weak' end is static - this reduces the chance of the weak end becoming coil bound (often the cause of spring failure) under shock load. When I was involved with Club spares, I got a lot of enquiries about broken springs - my advice was to turn the springs upside-down to reduce the chance of them ever becoming coil bound.

Regards,
               Eddie.

Offline isettaman

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Re: Mark Front Forks Question
« Reply #4 on: 21 Jul 2019 at 21:31 »
Thanks for the information, Eddie. I have the straight springs with no taper so hopefully no broken spring problems.

Dave

Offline tck

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Re: Mark Front Forks Question
« Reply #5 on: 25 Jul 2019 at 15:01 »
That solves the puzzle of fifty years ago when I found dozens of half rings of square section springs in my first Mk Douglas...