74 750 GT 38mm Marzocchi forks

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Bern
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74 750 GT 38mm Marzocchi forks

Post by Bern » Mon Aug 06, 2012 6:51 am

How much fork oil is required I have read 230cc and 250cc Also is the procedure for refilling documented anywhere?

Manual says 280cc

Thanks
B

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Re: 74 750 GT 38mm Marzocchi forks

Post by BevHevSteve » Mon Aug 06, 2012 3:09 pm

http://www.bevelheaven.com/ForkCap.htm

use a Hite Rite to measure out what you need..
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Bern
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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Mon Aug 06, 2012 5:19 pm

Perfect thanks.

Bern
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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Tue Aug 07, 2012 3:51 am

How much preload is too much preload? I found a couple of spacers around 2.5 cm long at the top of my forks when I disassembled them. I'm wondering if the previous owner found the springs to be shot and went down this road as opposed to replacing them.

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Re: 74 750 GT 38mm Marzocchi forks

Post by welshmally » Tue Aug 07, 2012 12:33 pm

Got these in my '80 900SS - leave 'em in, as I found that without them, the front end takes on the feel of over-cooked pasta!!! :-D

According to Steve, they are meant to be there - another poster suggested using suitably-sized coins to 'fine tune' the pre-load. I don't think I'm good enough to notice the difference........

Bern
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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Sat Aug 11, 2012 4:50 am

One more question. I had the front forks right off and disassembled when I rebuilt them. They needed a pretty good cleaning, One thing I notice now is that the centre shaft for the triple clamp seems to have slipped down a bit. I used a rubber mallet when 'tapping' the triple clamp back onto the forks. At the bottom of the triple clamp I think the centre stem is protruding too far down. How far should this protrude? Do I need to tap it back in until the lip? It seems like the whole steering column could loosen.


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morini
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Re: 74 750 GT 38mm Marzocchi forks

Post by morini » Thu Aug 16, 2012 2:13 pm

Are you sure it's moving? The stem is tapered and pressed into place with considerable force so they're a pretty tight fit. The part to can see protruding is supposed to be protruding. The steering stop plate usually slips over it.
I can't see how the stem could drop because it's screwed together by the crown nut, the adjuster and then both triple clamps are locked by their own bolts. Unless someone starts bashing it down wards it shouldn't come out.
Have a look at an exploded parts diagram and you'll see what I mean.

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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Thu Aug 16, 2012 3:32 pm

I'm not sure it moved but it seems that there is too much protruding. I had the forks completely disassembled and rebuilt them. When I was putting the lower part of the triple clamp back on the forks I tapped it into position with a rubber mallet. The washer and nut for the steering damper are way to sloppy now so it seems like it did slip. I was hoping that someone could take a peak at theirs. I suspect I need to tap the centre stem back up with the steering stem completely disassembled and then snug everything back up.

morini
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Re: 74 750 GT 38mm Marzocchi forks

Post by morini » Thu Aug 16, 2012 4:58 pm

Are you saying you removed the stem? You'd need a press to do that.

Mine protrudes the same amount. Is it loose? Yours looks normal to me.

Bern
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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Sun Aug 19, 2012 3:38 am

No I didn't remove the stem. I had the chance to measure the protrusion on someone else's 900ss and it was 12mm. I'll measure mine today.

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Re: 74 750 GT 38mm Marzocchi forks

Post by machten » Sun Aug 19, 2012 5:31 am

I'd agree that you don't have that in the right relative position. Did you play with head stock bearings at all?

In position it should look like this from a very pristine 73 750 Sport (and ignore the friction shaft length - they were always variable)

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Kev

Bern
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Re: 74 750 GT 38mm Marzocchi forks

Post by Bern » Sun Aug 19, 2012 6:28 am

Perfect!!! The lower washer was not sliding over the bottom lip on the stem. I had to tap it home a little harder to get it to seat and everything snugged up nicely.

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