'66 250 Scrambler fork questions

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ErikMVM
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'66 250 Scrambler fork questions

Post by ErikMVM »

Hi gang,

Working on restoring this bike and the forks are a bit of a mystery, I would be grateful for any help.

According to this manual...

https://www.ducatimeccanica.com/marzocc ... chi_13.htm

...it appears that a special "pin" tool is necessary to hold the damper rod while unscrewing the bolt from the bottom of the slider. Is this a thing that will have to be custom made, or is anyone aware of such a tool? Am I even looking at the right instructions?

I've also been going off of this schematic :
marzocchi_fork1.JPG
Are there any better or more useful manuals for this fork?

Here's a link to the Google Photos repository so you can see the fork in question: https://photos.app.goo.gl/iBoNg2foqbNk2iNH7

Thanks!
-erik
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Re: '66 250 Scrambler fork questions

Post by BevHevSteve »

If you are asking about getting screw #27 out of the bottom so everything comes apart, its easy to do just use an impact gun before you take the top cap off meaning, while everything is under tension. To put back together use an impact doesn't matter if the spring is holding pressure or not it will spin fast enough to grab and tighten.
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Craig in France
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Re: '66 250 Scrambler fork questions

Post by Craig in France »

As Steve, Erik. You just need to block the rod from turning. So either 'surprise' it by using an impact gun. Or fashion up what Ducati called a "suitable T wrench".

Here's the Ducati illustration of the "suitable T-wrench". Not very helpful, it has to be said.

That fork manual you are using is not the correct one. Ok, the working principals of a telescopic fork haven't changed much over the years; but that manual is for a much later model from the 1980s, complete with provision for brake discs!

To be continued ....
Attachments
T wrench.jpg
Last edited by Craig in France on Wed Apr 26, 2023 1:23 am, edited 4 times in total.
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Craig in France
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Re: '66 250 Scrambler fork questions

Post by Craig in France »

Also:
The correct original factory workshop manual for your bike looks like this:
Manual.jpg

Or this (a reprint):
Factory late reprint grey cover.jpg

Just be aware there was an earlier factory manual which does not cover your bike. It has a blue cover:
Factory early.jpg
To be continued ...
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Craig in France
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Re: '66 250 Scrambler fork questions

Post by Craig in France »

Otherwise, Clymer published several reprints of the factory manual. Copies of these tend to be more easily found - ebay and the like. They typically look like this (see the Clymer name at bottom left):
Clymer orange cover v2.jpg
(There are 2 further editions, but for the sake of brevity I shall refrain from publishing photos of these).

There is also Tom Bailey's "Ducati Singles" Masterbook. This includes Tom's observations when thing are less clear than they might be ...
Bailey reprint.jpg

Don't buy the Haynes manual. it's for the later wide-case bikes.
ErikMVM
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Re: '66 250 Scrambler fork questions

Post by ErikMVM »

Awesome, thank you both for the helpful replies!

-Erik
ErikMVM
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Re: '66 250 Scrambler fork questions

Post by ErikMVM »

Hello beautiful people, I could use some more tribal knowledge for this fork.

The owner wanted to have the fork's "bottom yoke" chromed, along with a lot of the other parts. Unfortunately the folks that did the chroming decided to attach one of their dipping cables to the head tube threads. They didn't clean it up at all and so I was left with having to deal with it. After some very careful filing I got the threads cleaned up pretty well but the shaft securing nut on the damper won't screw on so I believe I need to hit it with a die to clean up the threads. I've searched the webs all over but cannot find the official thread pitch and diameter for this. My measurements show it to be either 25mm or 1 inch diameter with a 1.0 thread pitch being the closest. I'm hoping someone can confirm this. I'll attach a couple pics and of course a pic of the fork itself so you can see the prettyness.

Or should I just find a good machine shop?

Thanks and cheers,
-erik

p.s only the yoke is chromed, the lower tubes are polished aluminum finish :-D
Attachments
marzocchi_bling.jpg
marzocchi_pitch.jpg
marzocchi_diamater.jpg
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Craig in France
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Re: '66 250 Scrambler fork questions

Post by Craig in France »

26 x 1, the part number for the nut being 0460.37.110.

(I guess you're aware that the threaded end of the steering stem should be on the top not the bottom?)
SCR nc front fork.jpg
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